Co-reporter:Robin B. BedfordJohn G. Bowen, Carolina Méndez-Gálvez
The Journal of Organic Chemistry 2017 Volume 82(Issue 3) pp:
Publication Date(Web):January 13, 2017
DOI:10.1021/acs.joc.6b02970
2-Benzyl-N-tosylbenzamides and related substrates undergo copper-catalyzed intramolecular sulfamidation at the benzylic methylene to give N-arylsuflonyl-1-arylisoindolinones, which can be N-deprotected using samarium iodide to generate the free 1-arylisoindolinones. Preliminary mechanistic studies indicate that the rate-determining step is not C–H bond cleavage but are instead consistent with slow oxidation of a copper π-arene intermediate.
Co-reporter:Soneela Asghar;Sanita B. Tailor;Dr. David Elorriaga; Dr. Robin B. Bedford
Angewandte Chemie International Edition 2017 Volume 56(Issue 51) pp:16367-16370
Publication Date(Web):2017/12/18
DOI:10.1002/anie.201710053
AbstractReadily accessed cobalt pre-catalysts with N-heterocyclic carbene ligands catalyze the Suzuki cross-coupling of aryl chlorides and bromides with alkyllithium-activated arylboronic pinacolate esters. Preliminary mechanistic studies indicate that the cobalt species is reduced to Co0 during the reaction.
Co-reporter:Soneela Asghar;Sanita B. Tailor;Dr. David Elorriaga; Dr. Robin B. Bedford
Angewandte Chemie 2017 Volume 129(Issue 51) pp:16585-16588
Publication Date(Web):2017/12/18
DOI:10.1002/ange.201710053
AbstractReadily accessed cobalt pre-catalysts with N-heterocyclic carbene ligands catalyze the Suzuki cross-coupling of aryl chlorides and bromides with alkyllithium-activated arylboronic pinacolate esters. Preliminary mechanistic studies indicate that the cobalt species is reduced to Co0 during the reaction.
Co-reporter:Robin B. Bedford, Peter B. Brenner, Steven J. Durrant, Timothy Gallagher, Carolina Méndez-Gálvez, and Michelle Montgomery
The Journal of Organic Chemistry 2016 Volume 81(Issue 9) pp:3473-3478
Publication Date(Web):April 8, 2016
DOI:10.1021/acs.joc.6b00532
The palladium-catalyzed ortho-arylation of diethyl carbamate-protected estrone and estriol with aryl iodides gives the 2-arylated analogues. Subsequent removal of the carbamate directing group furnishes 2-arylated estrone, estradiol, or estriol depending on the method used.
Co-reporter:Robin B. Bedford
Accounts of Chemical Research 2015 Volume 48(Issue 5) pp:1485
Publication Date(Web):April 28, 2015
DOI:10.1021/acs.accounts.5b00042
The catalytic cross-coupling reactions of organic halides or related substrates with organometallic nucleophiles form the cornerstone of many carbon–carbon bond-forming processes. While palladium-based catalysts typically mediate such reactions, there are increasing concerns about the long-term sustainability of palladium in synthesis. This is due to the high cost of palladium, coupled with its low natural abundance, environmentally deleterious extraction (∼6 g of metal are produced per ton of ore), toxicity, and competition for its use from the automotive and consumer electronics sectors. Therefore, there is a growing interest in replacing palladium-based catalysts with those incorporating more earth-abundant elements.With its low cost, high natural abundance, and low toxicity, iron makes a particularly appealing alternative, and accordingly, the development of iron-catalyzed cross-coupling is undergoing explosive growth. However, our understanding of the mechanisms that underpin the iron-based catalytic cycles is still very much in its infancy. Mechanistic insight into catalytic reactions is not only academically important but also allows us to maximize the efficiency of processes or even to develop entirely new transformations.Key to the development of robust mechanistic models for cross-coupling is knowing the lowest oxidation state in the cycle. Once this is established, we can explore subsequent redox processes and build the catalytic manifold. Until we know with confidence what the lowest oxidation state is, any cycles proposed are largely just guesswork.To date, Fe(−II), Fe(−I), Fe(0), Fe(I), and Fe(II) have been proposed as contenders for the lowest-oxidation-state species in the cycle in iron-catalyzed cross-coupling; the aim of this Account is to pull together the various pieces of evidence in support, or otherwise, of each of these suggestions in turn.There currently exists no direct evidence that oxidation states below Fe(0) are active in the catalytic cycle. Meanwhile, the reactivity required of the lowest-oxidation-state species has been observed with model compounds in higher oxidation states, implying that there is no need to invoke such low oxidation states. While subzero-valent complexes do indeed act as effective precatalysts, it is important to recognize that this tells us that they are efficiently converted to an active catalyst but says nothing about the oxidation states of the species in the catalytic cycle.Zero-valent heterogeneous iron nanoparticles can be formed under typical catalytic conditions, but there is no evidence to suggest that homogeneous Fe(0) complexes can be produced under comparable conditions. It seems likely that the zero-valent nanoparticles act as a reservoir for soluble higher-oxidation-state species.Fe(II) complexes can certainly be formed under catalytically relevant conditions, and when bulky nucleophilic coupling partners are exploited, potential intermediates can be isolated. However, the bulky reagents act as poor proxies for most nucleophiles used in cross-coupling, as they give Fe(II) organometallic intermediates that are kinetically stabilized with respect to reductive elimination. When more realistic substrates are exploited, reduction or disproportionation to Fe(I) is widely observed, and while it still has not been conclusively proved, this oxidation state currently represents a likely candidate for the lowest one active in many iron-catalyzed cross-coupling processes.
Co-reporter:Dr. Robin B. Bedford;John G. Bowen;Russell B. Davidson;Dr. Mairi F. Haddow;Annabelle E. Seymour-Julen;Dr. Hazel A. Sparkes;Dr. Ruth L. Webster
Angewandte Chemie 2015 Volume 127( Issue 22) pp:6691-6694
Publication Date(Web):
DOI:10.1002/ange.201500620
Abstract
Palladium(II) acetate is readily converted into [Pd3(μ2-OH)(OAc)5] (1) in the presence of water in a range of organic solvents and is also slowly converted in the solid state. Complex 1 can also be formed in nominally anhydrous solvents. Similarly, the analogous alkoxide complexes [Pd3(μ2-OR)(OAc)5] (3) are easily formed in solutions of palladium(II) acetate containing a range of alcohols. An examination of a representative Wacker-type oxidation shows that the Pd-OH complex 1 and a related Pd-oxo complex 4 can be excluded as potential catalytic intermediates in the absence of exogenous water.
Co-reporter:Dr. Robin B. Bedford;Dr. Steven J. Durrant;Michelle Montgomery
Angewandte Chemie 2015 Volume 127( Issue 30) pp:8911-8914
Publication Date(Web):
DOI:10.1002/ange.201502150
Abstract
The regiodivergent palladium-catalyzed CH arylation of pyrazolo[1,5-a]pyrimidine has been achieved, wherein the switch in regioselectivity between positions C3 and C7 is under complete catalyst control. A phosphine-containing palladium catalyst promotes the direct arylation at the most acidic position (C7), whereas a phosphine-free catalyst targets the most electron-rich position (C3).
Co-reporter:Dr. Robin B. Bedford;Dr. Steven J. Durrant;Michelle Montgomery
Angewandte Chemie International Edition 2015 Volume 54( Issue 30) pp:8787-8790
Publication Date(Web):
DOI:10.1002/anie.201502150
Abstract
The regiodivergent palladium-catalyzed CH arylation of pyrazolo[1,5-a]pyrimidine has been achieved, wherein the switch in regioselectivity between positions C3 and C7 is under complete catalyst control. A phosphine-containing palladium catalyst promotes the direct arylation at the most acidic position (C7), whereas a phosphine-free catalyst targets the most electron-rich position (C3).
Co-reporter:Dr. Robin B. Bedford;John G. Bowen;Russell B. Davidson;Dr. Mairi F. Haddow;Annabelle E. Seymour-Julen;Dr. Hazel A. Sparkes;Dr. Ruth L. Webster
Angewandte Chemie International Edition 2015 Volume 54( Issue 22) pp:6591-6594
Publication Date(Web):
DOI:10.1002/anie.201500620
Abstract
Palladium(II) acetate is readily converted into [Pd3(μ2-OH)(OAc)5] (1) in the presence of water in a range of organic solvents and is also slowly converted in the solid state. Complex 1 can also be formed in nominally anhydrous solvents. Similarly, the analogous alkoxide complexes [Pd3(μ2-OR)(OAc)5] (3) are easily formed in solutions of palladium(II) acetate containing a range of alcohols. An examination of a representative Wacker-type oxidation shows that the Pd-OH complex 1 and a related Pd-oxo complex 4 can be excluded as potential catalytic intermediates in the absence of exogenous water.
Co-reporter:Dr. Robin B. Bedford;Dr. Peter B. Brenner;Dr. Emma Carter;Paul M. Cogswell;Dr. Mairi F. Haddow;Dr. Jeremy N. Harvey;Dr. Damien M. Murphy;Joshua Nunn;Dr. Christopher H. Woodall
Angewandte Chemie International Edition 2014 Volume 53( Issue 7) pp:1804-1808
Publication Date(Web):
DOI:10.1002/anie.201308395
Abstract
The reactions of iron chlorides with mesityl Grignard reagents and tetramethylethylenediamine (TMEDA) under catalytically relevant conditions tend to yield the homoleptic “ate” complex [Fe(mes)3]− (mes=mesityl) rather than adducts of the diamine, and it is this ate complex that accounts for the catalytic activity. Both [Fe(mes)3]− and the related complex [Fe(Bn)3]− (Bn=benzyl) react faster with representative electrophiles than the equivalent neutral [FeR2(TMEDA)] complexes. FeI species are observed under catalytically relevant conditions with both benzyl and smaller aryl Grignard reagents. The X-ray structures of [Fe(Bn)3]− and [Fe(Bn)4]− were determined; [Fe(Bn)4]− is the first homoleptic σ-hydrocarbyl FeIII complex that has been structurally characterized.
Co-reporter:Dr. Robin B. Bedford;Dr. Peter B. Brenner;Dr. Emma Carter;Paul M. Cogswell;Dr. Mairi F. Haddow;Dr. Jeremy N. Harvey;Dr. Damien M. Murphy;Joshua Nunn;Dr. Christopher H. Woodall
Angewandte Chemie 2014 Volume 126( Issue 7) pp:1835-1839
Publication Date(Web):
DOI:10.1002/ange.201308395
Abstract
Eisenchloride bilden mit Mesityl-Grignard-Reagentien und Tetramethylethylendiamin (TMEDA) unter katalyserelevanten Bedingungen nicht den entsprechenden Diaminkomplex, sondern den homoleptischen at-Komplex [Fe(mes)3]− (mes=Mesityl), der die katalytische Aktivität gewährleistet. Sowohl [Fe(mes)3]− als auch [Fe(Bn)3]− (Bn=Benzyl) reagieren mit repräsentativen Elektrophilen schneller als die entsprechenden neutralen [FeR2(TMEDA)]-Komplexe. Mit Benzyl- oder kleineren Grignard-Reagentien werden zudem FeI-Spezies beobachtet. Die Festkörpermolekülstrukturen von [Fe(Bn)3]− und [Fe(Bn)4]− wurden bestimmt. [Fe(Bn)4]− ist der erste strukturell charakterisierte homoleptische Eisen(III)-σ-Organylkomplex.
Co-reporter:Robin B. Bedford, Peter B. Brenner, Emma Carter, Jamie Clifton, Paul M. Cogswell, Nicholas J. Gower, Mairi F. Haddow, Jeremy N. Harvey, Jeffrey A. Kehl, Damien M. Murphy, Emily C. Neeve, Michael L. Neidig, Joshua Nunn, Benjamin E. R. Snyder, and Joseph Taylor
Organometallics 2014 Volume 33(Issue 20) pp:5767-5780
Publication Date(Web):August 5, 2014
DOI:10.1021/om500518r
Iron phosphine complexes prove to be good precatalysts for the cross-coupling of alkyl, benzyl, and allyl halides with not only aryl triorganoborate salts but also related aluminum-, gallium-, indium-, and thallium-based nucleophiles. Mechanistic studies revealed that while Fe(I) can be accessed on catalytically relevant time scales, lower average oxidation states are not formed fast enough to be relevant to catalysis. EPR spectroscopic studies reveal the presence of bis(diphosphine)iron(I) complexes in representative catalytic reactions and related processes with a range of group 13 nucleophiles. Isolated examples were studied by Mössbauer spectroscopy and single-crystal X-ray structural analysis, while the electronic structure was probed by dispersion-corrected B3LYP DFT calculations. An EPR study on an iron system with a bulky diphosphine ligand revealed the presence of an S = 1/2 species consistent with the formation of a mono(diphosphine)iron(I) species with inequivalent phosphine donor environments. DFT analysis of model complexes allowed us to rule out a T-shaped Fe(I) structure, as this is predicted to be high spin.
Co-reporter:Dr. Robin B. Bedford;Dr. Peter B. Brenner;Dr. Emma Carter;Thomas W. Carvell;Paul M. Cogswell;Dr. Timothy Gallagher;Dr. Jeremy N. Harvey;Dr. Damien M. Murphy;Dr. Emily C. Neeve;Joshua Nunn;Dominic R. Pye
Chemistry - A European Journal 2014 Volume 20( Issue 26) pp:7935-7938
Publication Date(Web):
DOI:10.1002/chem.201402174
Abstract
While attractive, the iron-catalyzed coupling of arylboron reagents with alkyl halides typically requires expensive or synthetically challenging diphosphine ligands. Herein, we show that primary and secondary alkyl bromides and chlorides, as well as benzyl and allyl halides, can be coupled with arylboronic esters, activated with alkyllithium reagents, by using very simple iron-based catalysts. The catalysts used were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co- ligands. In the former case, preliminary mechanistic studies highlight the likely involvement of iron(I)–phosphine intermediates.
Co-reporter:Martin Albrecht (Guest Editor) , Robin Bedford (Guest Editor) , Bernd Plietker
Organometallics 2014 Volume 33(Issue 20) pp:5619-5621
Publication Date(Web):October 27, 2014
DOI:10.1021/om5010379
Co-reporter:Robin B. Bedford, John G. Bowen, Amanda L. Weeks
Tetrahedron 2013 69(22) pp: 4389-4394
Publication Date(Web):
DOI:10.1016/j.tet.2013.02.055
Co-reporter:Dr. Robin B. Bedford;Dr. Emma Carter;Paul M. Cogswell;Nicholas J. Gower;Dr. Mairi F. Haddow;Dr. Jeremy N. Harvey;Dr. Damien M. Murphy;Emily C. Neeve;Joshua Nunn
Angewandte Chemie International Edition 2013 Volume 52( Issue 4) pp:1285-1288
Publication Date(Web):
DOI:10.1002/anie.201207868
Co-reporter:Dr. Robin B. Bedford;Dr. Emma Carter;Paul M. Cogswell;Nicholas J. Gower;Dr. Mairi F. Haddow;Dr. Jeremy N. Harvey;Dr. Damien M. Murphy;Emily C. Neeve;Joshua Nunn
Angewandte Chemie 2013 Volume 125( Issue 4) pp:1323-1326
Publication Date(Web):
DOI:10.1002/ange.201207868
Co-reporter:Christopher J. Adams ; Robin B. Bedford ; Emma Carter ; Nicholas J. Gower ; Mairi F. Haddow ; Jeremy N. Harvey ; Michael Huwe ; M. Ángeles Cartes ; Stephen M. Mansell ; Carla Mendoza ; Damien M. Murphy ; Emily C. Neeve ;Joshua Nunn
Journal of the American Chemical Society 2012 Volume 134(Issue 25) pp:10333-10336
Publication Date(Web):June 13, 2012
DOI:10.1021/ja303250t
Herein we demonstrate both the importance of Fe(I) in Negishi cross-coupling reactions with arylzinc reagents and the isolation of catalytically competent Fe(I) intermediates. These complexes, [FeX(dpbz)2] [X = 4-tolyl (7), Cl (8a), Br (8b); dpbz = 1,2-bis(diphenylphosphino)benzene], were characterized by crystallography and tested for activity in representative reactions. The complexes are low-spin with no significant spin density on the ligands. While complex 8b shows performance consistent with an on-cycle intermediate, it seems that 7 is an off-cycle species.
Co-reporter:Dr. Robin B. Bedford;Nicholas J. Gower;Dr. Mairi F. Haddow;Dr. Jeremy N. Harvey;Joshua Nunn;Rukeme A. Okopie ;Dr. Rosalind F. Sankey
Angewandte Chemie 2012 Volume 124( Issue 22) pp:5531-5534
Publication Date(Web):
DOI:10.1002/ange.201202219
Co-reporter:Dr. Robin B. Bedford;Nicholas J. Gower;Dr. Mairi F. Haddow;Dr. Jeremy N. Harvey;Joshua Nunn;Rukeme A. Okopie ;Dr. Rosalind F. Sankey
Angewandte Chemie International Edition 2012 Volume 51( Issue 22) pp:5435-5438
Publication Date(Web):
DOI:10.1002/anie.201202219
Co-reporter:Robin B. Bedford, Natalie Fey, Mairi F. Haddow and Rosalind F. Sankey
Chemical Communications 2011 vol. 47(Issue 12) pp:3649-3651
Publication Date(Web):16 Feb 2011
DOI:10.1039/C0CC05033D
Palladium-catalysed dearomatisation reactions allow access to a previously unknown class of indoloindole heterocycle: 5,10b-dihydroindolo[2,3-b]indoles. The highly reactive nature of these compounds is demonstrated by their facile reactions with water and with hydride, alkyl, aryl and allyl-based organometallic nucleophiles.
Co-reporter:Robin B. Bedford, Yu-Ning Chang, Mairi F. Haddow and Claire L. McMullin
Dalton Transactions 2011 vol. 40(Issue 35) pp:9034-9041
Publication Date(Web):05 Aug 2011
DOI:10.1039/C1DT10356C
A range of chiral resorcinol bis(phosphite) and phosphite–phosphinite ligands were produced and their propensity to form palladiumPCP-pincer complexes examined. The ease of base-assisted C–H palladation of the ligands falls in the order bis(phosphinite) > phosphite–phosphinite > bis(phosphite). The catalytic activity of the complexes in the asymmetric allylation of benzaldehyde with allyl tributyltin was examined and it was found that, contrary to expectations, ligands with 3,3′-disubstituted BINOL residues show poorer activity and stereoselectivity than unsubstituted BINOL analogues. In addition the order of activity of the pincer complexes was established as bis(phosphite) > phosphite–phosphinite > bis(phosphinite). Crystal structures of representative examples of a 3,3′-disubstituted BINOL, mono- and bis(phosphite) ligands based on 2,4-di-tert-butyl resorcinol and Pd complexes of two of the chiral complexes are presented.
Co-reporter:Robin B. Bedford, Yu-Ning Chang, Mairi F. Haddow and Claire L. McMullin
Dalton Transactions 2011 vol. 40(Issue 35) pp:9042-9050
Publication Date(Web):05 Aug 2011
DOI:10.1039/C1DT10357A
The reactions of a range of chiral resorcinol monophosphite ligands with [PdCl2(NCMe)2] was investigated in order to establish whether the meta-hydroxyl function was involved in the orthometallation processes. These ligands underwent facile orthopalladation at room temperature in the presence of Et3N, whilst the equivalent hydroxyl-free analogues needed more forcing conditions to induce orthometallation. When the hydroxyl function was replaced by a similar sized methyl group no orthometallation occurred, even on heating. Furthermore the hydroxyl group influences both the structure and isomerism in the resultant palladacycles viahydrogen bonding to adjacent chloride ligands. Similarly, the hydroxyl function leads to higher enantiocontrol in the asymmetric allylation of benzaldehyde with allyl tributyltin. Representative examples of the ligands and the palladium complexes obtained were characterised by single crystal X-ray diffraction.
Co-reporter: Robin B. Bedford;Dr. Mairi F. Haddow;Charlotte J. Mitchell;Ruth L. Webster
Angewandte Chemie 2011 Volume 123( Issue 24) pp:5638-5641
Publication Date(Web):
DOI:10.1002/ange.201101606
Co-reporter: Robin B. Bedford;Dr. Mairi F. Haddow;Charlotte J. Mitchell;Ruth L. Webster
Angewandte Chemie International Edition 2011 Volume 50( Issue 24) pp:5524-5527
Publication Date(Web):
DOI:10.1002/anie.201101606
Co-reporter:Robin B. Bedford, Charlotte J. Mitchell and Ruth L. Webster
Chemical Communications 2010 vol. 46(Issue 18) pp:3095-3097
Publication Date(Web):30 Mar 2010
DOI:10.1039/C003074K
Solvent-free reaction conditions facilitate a range of aromatic C–H functionalisations that traditionally require acidic or disfavoured solvents. These reactions include selective ortho- and meta-arylation of aryl carbamates and anilides and selective halogenation reactions.
Co-reporter:Robin B. Bedford, Jens U. Engelhart, Mairi F. Haddow, Charlotte J. Mitchell and Ruth L. Webster
Dalton Transactions 2010 vol. 39(Issue 43) pp:10464-10472
Publication Date(Web):08 Oct 2010
DOI:10.1039/C0DT00385A
The solvent-free, palladium-catalysed reaction of anilides with CuCl2 in the presence or absence of copper acetate yields ortho-chlorinated anilides in good to excellent yields, even on a large scale (100 mmol). By contrast, the equivalent reactions with copper bromide, either solvent free or in 1,2-dichloroethane, in the presence or absence of palladium, under air or inert conditions, gave the products of simple electrophilic bromination. Mechanistic studies highlighted the involvement of palladacyclic intermediates, one of which was characterised crystallographically, which undergo subsequent reaction with copper(II) chloride to yield the chlorinated anilide products.
Co-reporter:Robin B. Bedford, Craig P. Butts, Mairi F. Haddow, Robert Osborne and Rosalind F. Sankey
Chemical Communications 2009 (Issue 32) pp:4832-4834
Publication Date(Web):14 Jul 2009
DOI:10.1039/B910894G
Despite their intrinsic instability, 4a-alkyl-4aH-carbazoles can be generated by a catalytic dearomatisation process; their reactivity is demonstrated by facile dealkylation and highly unusual cyclodimerisation processes.
Co-reporter:Robin B. Bedford, Michael Huwe and Mark C. Wilkinson
Chemical Communications 2009 (Issue 5) pp:600-602
Publication Date(Web):11 Dec 2008
DOI:10.1039/B818961G
Iron-based catalysts containing either 1,2-bis(diphenylphosphino)benzene or 1,3-bis(diphenylphosphino)propane give excellent activity and good selectivity in the Negishi coupling of aryl zinc reagents with a range of benzylhalides and phosphates.
Co-reporter:Robin B. Bedford, Mark A. Hall, George R. Hodges, Michael Huwe and Mark C. Wilkinson
Chemical Communications 2009 (Issue 42) pp:6430-6432
Publication Date(Web):28 Sep 2009
DOI:10.1039/B915945B
Employing co-catalytic zinc reagents facilitates the iron-catalysed Suzuki cross-coupling of tetraarylborates with both benzyl and 2-heteroaryl halides.
Co-reporter:Robin B. Bedford, Mairi F. Haddow, Ruth L. Webster and Charlotte J. Mitchell
Organic & Biomolecular Chemistry 2009 vol. 7(Issue 15) pp:3119-3127
Publication Date(Web):15 Jun 2009
DOI:10.1039/B906119C
The rhodium-catalysed direct ortho-arylation of protected racemic 2-tert-butyl tyrosine has been developed. The subsequent removal of the tert-butyl group yields the 2-arylated tyrosine which can undergo further rhodium-based arylation at the 6-position. In one instance a product formed by further arylation of the diarylated species was isolated.
Co-reporter:Robin B. Bedford, Helena Dumycz, Mairi F. Haddow, Lukasz T. Pilarski, A. Guy Orpen, Paul G. Pringle and Richard L. Wingad
Dalton Transactions 2009 (Issue 37) pp:7796-7804
Publication Date(Web):31 Jul 2009
DOI:10.1039/B907333G
The optically pure monophosphites P(OAr)(BINOLate) (7, where Ar = 2,4-di-tert-butylphenyl) have been prepared by treatment of PCl2(OAr) with R- or S-BINOL. Treatment of [PdCl2(NCMe)2] with 7 gave [PdCl2(7)2] (9) or the binuclear orthometallated complex [Pd2Cl2(7-H)2] (8) depending on the reaction conditions. Bridge cleavage reactions of 8 gave [PdCl(7-H)(L)] with L trans to carbon when L = PPh3 or 7 and cis to carbon when L = N-heterocyclic carbene. Treatment of [PtCl2(NCtBu)2] with 7 gave [PtCl2(7)2] (18) which upon further reaction with PtCl2 furnished a mixture of binuclear [Pt2Cl2(7-H)2] (17) and cis-[PtCl(7-H)(7)] (19). The palladium complexes containing cyclometallated 7 were screened for catalysis of 1,4-conjugate addition of phenylboronic acid to cyclohexen-2-one and the allylation of benzaldehyde with allyltributyltin. Conversions were generally high in each case but enantioselectivities were low (15% e.e. at best). The X-ray crystal structures of 8, 17 and [PdCl(7-H)(NHC)] (10a, where NHC = 1,3-(dimesityl)imidazolidin-2-ylidene) have been determined.
Co-reporter:Robin B. Bedford, Ruth L. Webster and Charlotte J. Mitchell
Organic & Biomolecular Chemistry 2009 vol. 7(Issue 23) pp:4853-4857
Publication Date(Web):30 Sep 2009
DOI:10.1039/B916724M
The carbamate (–O2CNR2) function is an excellent directing group for palladium-catalysed direct arylation reactions giving both protected or free mono- or di-substituted phenols, as well as an example of a dibenzopyranone, depending on coupling partners (aryl iodides or diaryliodonium salts) and conditions.
Co-reporter:Robin B. Bedford, Masaharu Nakamura, Nicholas J. Gower, Mairi F. Haddow, Mark A. Hall, Michael Huwe, Tohru Hashimoto, Rukeme A. Okopie
Tetrahedron Letters 2009 50(45) pp: 6110-6111
Publication Date(Web):
DOI:10.1016/j.tetlet.2009.08.022
Co-reporter:Robin B. Bedford, Michael Betham, Craig P. Butts, Simon J. Coles, Michael B. Hursthouse, P. Noelle Scully, James H. R. Tucker, John Wilkie and Yasmine Willener
Chemical Communications 2008 (Issue 21) pp:2429-2431
Publication Date(Web):23 Apr 2008
DOI:10.1039/B801823E
A novel organometallic receptor binds anions in solution and in the solid state, with complexes stabilised through a series of C–H⋯X interactions, as evidenced by 1H NMR spectroscopy, X-ray crystallography and computational models.
Co-reporter:Robin B. Bedford, Michael Betham, Andrew J. M. Caffyn, Jonathan P. H. Charmant, Lesley C. Lewis-Alleyne, Philip D. Long, Dorian Polo-Cerón and Sanjiv Prashar
Chemical Communications 2008 (Issue 8) pp:990-992
Publication Date(Web):10 Jan 2008
DOI:10.1039/B718128K
Simple chlorodiisopropylphosphine adducts of rhodium, either pre-formed or formed in situ, prove to be highly effective catalysts for the ortho-arylation of phenols.
Co-reporter:Robin B. Bedford, Michael Betham, Craig P. Butts, Simon J. Coles, Marica Cutajar, Thomas Gelbrich, Michael B. Hursthouse, P. Noelle Scully and Stephen Wimperis
Dalton Transactions 2007 (Issue 4) pp:459-466
Publication Date(Web):12 Dec 2006
DOI:10.1039/B613524B
The reaction of the orthopalladated triarylphosphite complexes [{Pd(µ-Cl){κ2-P,C-P(OC6H2-2,4-R2)(OC6H3-2,4-R2)}2] (R = H, tBu) with bis(2-diphenylphosphinoethyl)phenylphosphine leads to a five-coordinate palladium(II) (R = H) and a mixture containing four-and five-coordinate species (R = tBu). The crystal structure of the five-coordinate species [Pd{κ2-P,C-(P(OC6H4)(OC6H5)2}{bis(2-diphenylphosphinoethyl)phenylphosphine}][SbF6] is presented. This complex reacts with hydrogen peroxide or [AuCl(tht)] to give four-coordinate complexes in which the displaced phosphine residue is either oxidised or coordinated to gold chloride; this demonstrates that the five-coordinate complexes are labile in solution. By contrast, the reactions of the dimeric precursors with 1,1,1-tris(diphenylphosphinomethyl)ethane give four-coordinate complexes in the solid state, although evidence is presented that the smaller phosphite-containing system is five-coordinate at room temperature or higher in solution.
Co-reporter:Robin B. Bedford, Michael Betham, Duncan W. Bruce, Sean A. Davis, Robert M. Frost and Michael Hird
Chemical Communications 2006 (Issue 13) pp:1398-1400
Publication Date(Web):03 Mar 2006
DOI:10.1039/B601014H
Iron nanoparticles, either formed in situ stabilized by 1,6-bis(diphenylphosphino)hexane or polyethylene glycol (PEG), or preformed stabilized by PEG, are excellent catalysts for the cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing β-hydrogens and they also prove effective in a tandem cyclization/cross-coupling reaction.
Co-reporter:R. Angharad Baber, Robin B. Bedford, Michael Betham, Michael E. Blake, Simon J. Coles, Mairi F. Haddow, Michael B. Hursthouse, A. Guy Orpen, Lukasz T. Pilarski, Paul G. Pringle and Richard L. Wingad
Chemical Communications 2006 (Issue 37) pp:3880-3882
Publication Date(Web):29 Aug 2006
DOI:10.1039/B609704A
The synthesis of a range of chiral palladium bis(phosphite) pincer complexes has been achieved via C–H activation of the parent ligands and one of the complexes formed shows good activity in the catalytic allylation of aldehydes.
Co-reporter:Robin B. Bedford, Michael Betham, Michael E. Blake, Simon J. Coles, Sylvia M. Draper, Michael B. Hursthouse, P. Noelle Scully
Inorganica Chimica Acta 2006 Volume 359(Issue 6) pp:1870-1878
Publication Date(Web):10 April 2006
DOI:10.1016/j.ica.2005.07.050
Co-reporter:Robin B. Bedford, Duncan W. Bruce, Robert M. Frost and Michael Hird
Chemical Communications 2005 (Issue 33) pp:4161-4163
Publication Date(Web):22 Jul 2005
DOI:10.1039/B507133J
Mixtures of iron(III) chloride and appropriate amine ligands are active catalysts for the coupling of aryl Grignard reagents with primary and secondary alkyl halide substrates bearing β-hydrogens, under mild and simple reaction conditions.
Co-reporter:Robin B. Bedford, Michael Betham, Michael E. Blake, Robert M. Frost, Peter N. Horton, Michael B. Hursthouse and Rosa-María López-Nicolás
Dalton Transactions 2005 (Issue 16) pp:2774-2779
Publication Date(Web):18 Jul 2005
DOI:10.1039/B506286A
Carbene adducts of orthopalladated triarylphosphite complexes have been synthesised and characterised. The structures of three of these complexes were determined by single-crystal X-ray analysis. The complexes are active in the Suzuki coupling of a range of aryl bromide substrates.
Co-reporter:Robin B. Bedford, Peter B. Brenner, David Elorriaga, Jeremy N. Harvey and Joshua Nunn
Dalton Transactions 2016 - vol. 45(Issue 40) pp:NaN15817-15817
Publication Date(Web):2016/06/16
DOI:10.1039/C6DT01823H
The application of a variety of iron complexes with chelating amine ligands as pre-catalysts in the representative cross-coupling of 4-tolylmagnesium bromide with cyclohexyl bromide was investigated. The results from this study indicate the performance of the pre-catalyst is inversely proportional to the strength of the chelate or macrocyclic effect of the amine ligand, as determined by the propensity of the ligand to be displaced from the iron centre by reaction with excess benzyl magnesium chloride. The findings from this study are consistent with a catalytic cycle wherein the chelating amine ligand is not coordinated to the iron centre during turnover.
Co-reporter:Robin B. Bedford, Ruth L. Webster and Charlotte J. Mitchell
Organic & Biomolecular Chemistry 2009 - vol. 7(Issue 23) pp:NaN4857-4857
Publication Date(Web):2009/09/30
DOI:10.1039/B916724M
The carbamate (–O2CNR2) function is an excellent directing group for palladium-catalysed direct arylation reactions giving both protected or free mono- or di-substituted phenols, as well as an example of a dibenzopyranone, depending on coupling partners (aryl iodides or diaryliodonium salts) and conditions.
Co-reporter:Robin B. Bedford, Helena Dumycz, Mairi F. Haddow, Lukasz T. Pilarski, A. Guy Orpen, Paul G. Pringle and Richard L. Wingad
Dalton Transactions 2009(Issue 37) pp:NaN7804-7804
Publication Date(Web):2009/07/31
DOI:10.1039/B907333G
The optically pure monophosphites P(OAr)(BINOLate) (7, where Ar = 2,4-di-tert-butylphenyl) have been prepared by treatment of PCl2(OAr) with R- or S-BINOL. Treatment of [PdCl2(NCMe)2] with 7 gave [PdCl2(7)2] (9) or the binuclear orthometallated complex [Pd2Cl2(7-H)2] (8) depending on the reaction conditions. Bridge cleavage reactions of 8 gave [PdCl(7-H)(L)] with L trans to carbon when L = PPh3 or 7 and cis to carbon when L = N-heterocyclic carbene. Treatment of [PtCl2(NCtBu)2] with 7 gave [PtCl2(7)2] (18) which upon further reaction with PtCl2 furnished a mixture of binuclear [Pt2Cl2(7-H)2] (17) and cis-[PtCl(7-H)(7)] (19). The palladium complexes containing cyclometallated 7 were screened for catalysis of 1,4-conjugate addition of phenylboronic acid to cyclohexen-2-one and the allylation of benzaldehyde with allyltributyltin. Conversions were generally high in each case but enantioselectivities were low (15% e.e. at best). The X-ray crystal structures of 8, 17 and [PdCl(7-H)(NHC)] (10a, where NHC = 1,3-(dimesityl)imidazolidin-2-ylidene) have been determined.
Co-reporter:Robin B. Bedford, Mairi F. Haddow, Ruth L. Webster and Charlotte J. Mitchell
Organic & Biomolecular Chemistry 2009 - vol. 7(Issue 15) pp:NaN3127-3127
Publication Date(Web):2009/06/15
DOI:10.1039/B906119C
The rhodium-catalysed direct ortho-arylation of protected racemic 2-tert-butyl tyrosine has been developed. The subsequent removal of the tert-butyl group yields the 2-arylated tyrosine which can undergo further rhodium-based arylation at the 6-position. In one instance a product formed by further arylation of the diarylated species was isolated.
Co-reporter:Robin B. Bedford, Michael Betham, Andrew J. M. Caffyn, Jonathan P. H. Charmant, Lesley C. Lewis-Alleyne, Philip D. Long, Dorian Polo-Cerón and Sanjiv Prashar
Chemical Communications 2008(Issue 8) pp:NaN992-992
Publication Date(Web):2008/01/10
DOI:10.1039/B718128K
Simple chlorodiisopropylphosphine adducts of rhodium, either pre-formed or formed in situ, prove to be highly effective catalysts for the ortho-arylation of phenols.
Co-reporter:Robin B. Bedford, Michael Betham, Craig P. Butts, Simon J. Coles, Michael B. Hursthouse, P. Noelle Scully, James H. R. Tucker, John Wilkie and Yasmine Willener
Chemical Communications 2008(Issue 21) pp:NaN2431-2431
Publication Date(Web):2008/04/23
DOI:10.1039/B801823E
A novel organometallic receptor binds anions in solution and in the solid state, with complexes stabilised through a series of C–H⋯X interactions, as evidenced by 1H NMR spectroscopy, X-ray crystallography and computational models.
Co-reporter:Robin B. Bedford, Yu-Ning Chang, Mairi F. Haddow and Claire L. McMullin
Dalton Transactions 2011 - vol. 40(Issue 35) pp:NaN9050-9050
Publication Date(Web):2011/08/05
DOI:10.1039/C1DT10357A
The reactions of a range of chiral resorcinol monophosphite ligands with [PdCl2(NCMe)2] was investigated in order to establish whether the meta-hydroxyl function was involved in the orthometallation processes. These ligands underwent facile orthopalladation at room temperature in the presence of Et3N, whilst the equivalent hydroxyl-free analogues needed more forcing conditions to induce orthometallation. When the hydroxyl function was replaced by a similar sized methyl group no orthometallation occurred, even on heating. Furthermore the hydroxyl group influences both the structure and isomerism in the resultant palladacycles viahydrogen bonding to adjacent chloride ligands. Similarly, the hydroxyl function leads to higher enantiocontrol in the asymmetric allylation of benzaldehyde with allyl tributyltin. Representative examples of the ligands and the palladium complexes obtained were characterised by single crystal X-ray diffraction.
Co-reporter:Robin B. Bedford, Yu-Ning Chang, Mairi F. Haddow and Claire L. McMullin
Dalton Transactions 2011 - vol. 40(Issue 35) pp:NaN9041-9041
Publication Date(Web):2011/08/05
DOI:10.1039/C1DT10356C
A range of chiral resorcinol bis(phosphite) and phosphite–phosphinite ligands were produced and their propensity to form palladiumPCP-pincer complexes examined. The ease of base-assisted C–H palladation of the ligands falls in the order bis(phosphinite) > phosphite–phosphinite > bis(phosphite). The catalytic activity of the complexes in the asymmetric allylation of benzaldehyde with allyl tributyltin was examined and it was found that, contrary to expectations, ligands with 3,3′-disubstituted BINOL residues show poorer activity and stereoselectivity than unsubstituted BINOL analogues. In addition the order of activity of the pincer complexes was established as bis(phosphite) > phosphite–phosphinite > bis(phosphinite). Crystal structures of representative examples of a 3,3′-disubstituted BINOL, mono- and bis(phosphite) ligands based on 2,4-di-tert-butyl resorcinol and Pd complexes of two of the chiral complexes are presented.
Co-reporter:Robin B. Bedford, Michael Huwe and Mark C. Wilkinson
Chemical Communications 2009(Issue 5) pp:NaN602-602
Publication Date(Web):2008/12/11
DOI:10.1039/B818961G
Iron-based catalysts containing either 1,2-bis(diphenylphosphino)benzene or 1,3-bis(diphenylphosphino)propane give excellent activity and good selectivity in the Negishi coupling of aryl zinc reagents with a range of benzylhalides and phosphates.
Co-reporter:Robin B. Bedford, Craig P. Butts, Mairi F. Haddow, Robert Osborne and Rosalind F. Sankey
Chemical Communications 2009(Issue 32) pp:
Publication Date(Web):
DOI:10.1039/B910894G
Co-reporter:Robin B. Bedford, Mark A. Hall, George R. Hodges, Michael Huwe and Mark C. Wilkinson
Chemical Communications 2009(Issue 42) pp:NaN6432-6432
Publication Date(Web):2009/09/28
DOI:10.1039/B915945B
Employing co-catalytic zinc reagents facilitates the iron-catalysed Suzuki cross-coupling of tetraarylborates with both benzyl and 2-heteroaryl halides.
Co-reporter:Robin B. Bedford, Charlotte J. Mitchell and Ruth L. Webster
Chemical Communications 2010 - vol. 46(Issue 18) pp:NaN3097-3097
Publication Date(Web):2010/03/30
DOI:10.1039/C003074K
Solvent-free reaction conditions facilitate a range of aromatic C–H functionalisations that traditionally require acidic or disfavoured solvents. These reactions include selective ortho- and meta-arylation of aryl carbamates and anilides and selective halogenation reactions.
Co-reporter:Robin B. Bedford, Natalie Fey, Mairi F. Haddow and Rosalind F. Sankey
Chemical Communications 2011 - vol. 47(Issue 12) pp:NaN3651-3651
Publication Date(Web):2011/02/16
DOI:10.1039/C0CC05033D
Palladium-catalysed dearomatisation reactions allow access to a previously unknown class of indoloindole heterocycle: 5,10b-dihydroindolo[2,3-b]indoles. The highly reactive nature of these compounds is demonstrated by their facile reactions with water and with hydride, alkyl, aryl and allyl-based organometallic nucleophiles.
Co-reporter:Robin B. Bedford, Michael Betham, Craig P. Butts, Simon J. Coles, Marica Cutajar, Thomas Gelbrich, Michael B. Hursthouse, P. Noelle Scully and Stephen Wimperis
Dalton Transactions 2007(Issue 4) pp:NaN466-466
Publication Date(Web):2006/12/12
DOI:10.1039/B613524B
The reaction of the orthopalladated triarylphosphite complexes [{Pd(µ-Cl){κ2-P,C-P(OC6H2-2,4-R2)(OC6H3-2,4-R2)}2] (R = H, tBu) with bis(2-diphenylphosphinoethyl)phenylphosphine leads to a five-coordinate palladium(II) (R = H) and a mixture containing four-and five-coordinate species (R = tBu). The crystal structure of the five-coordinate species [Pd{κ2-P,C-(P(OC6H4)(OC6H5)2}{bis(2-diphenylphosphinoethyl)phenylphosphine}][SbF6] is presented. This complex reacts with hydrogen peroxide or [AuCl(tht)] to give four-coordinate complexes in which the displaced phosphine residue is either oxidised or coordinated to gold chloride; this demonstrates that the five-coordinate complexes are labile in solution. By contrast, the reactions of the dimeric precursors with 1,1,1-tris(diphenylphosphinomethyl)ethane give four-coordinate complexes in the solid state, although evidence is presented that the smaller phosphite-containing system is five-coordinate at room temperature or higher in solution.
Co-reporter:Robin B. Bedford, Jens U. Engelhart, Mairi F. Haddow, Charlotte J. Mitchell and Ruth L. Webster
Dalton Transactions 2010 - vol. 39(Issue 43) pp:NaN10472-10472
Publication Date(Web):2010/10/08
DOI:10.1039/C0DT00385A
The solvent-free, palladium-catalysed reaction of anilides with CuCl2 in the presence or absence of copper acetate yields ortho-chlorinated anilides in good to excellent yields, even on a large scale (100 mmol). By contrast, the equivalent reactions with copper bromide, either solvent free or in 1,2-dichloroethane, in the presence or absence of palladium, under air or inert conditions, gave the products of simple electrophilic bromination. Mechanistic studies highlighted the involvement of palladacyclic intermediates, one of which was characterised crystallographically, which undergo subsequent reaction with copper(II) chloride to yield the chlorinated anilide products.
![1H-Pyrrole, 1-[(2S,3R)-2-hydroxy-1-oxo-3-phenyl-3-(phenylthio)propyl]-](http://img.cochemist.com/ccimg/880200/880175-77-9.png)
![1H-Pyrrole, 1-[(2S,3R)-2-hydroxy-1-oxo-3-phenyl-3-(phenylthio)propyl]-](http://img.cochemist.com/ccimg/880200/880175-77-9_b.png)
![1H-Pyrrole, 1-[[(2R,3S)-3-phenyloxiranyl]carbonyl]-](http://img.cochemist.com/ccimg/880200/880175-74-6.png)
![1H-Pyrrole, 1-[[(2R,3S)-3-phenyloxiranyl]carbonyl]-](http://img.cochemist.com/ccimg/880200/880175-74-6_b.png)
![1H-Pyrrole, 2,5-dihydro-1-[[(2R,3S)-3-phenyloxiranyl]carbonyl]-](http://img.cochemist.com/ccimg/880200/880175-72-4.png)
![1H-Pyrrole, 2,5-dihydro-1-[[(2R,3S)-3-phenyloxiranyl]carbonyl]-](http://img.cochemist.com/ccimg/880200/880175-72-4_b.png)
![Phosphinic amide, N-[(1R)-1-phenylethyl]-P,P-bis[(1S)-1-phenylethyl]-](http://img.cochemist.com/ccimg/643800/643726-36-7.png)
![Phosphinic amide, N-[(1R)-1-phenylethyl]-P,P-bis[(1S)-1-phenylethyl]-](http://img.cochemist.com/ccimg/643800/643726-36-7_b.png)
![[1,1'-Biphenyl]-2-ol, 3-(1,1-dimethylethyl)-4'-ethenyl-](http://img.cochemist.com/ccimg/624000/623941-48-0.png)
![[1,1'-Biphenyl]-2-ol, 3-(1,1-dimethylethyl)-4'-ethenyl-](http://img.cochemist.com/ccimg/624000/623941-48-0_b.png)
![Pyrrolidine, 1-[[(2R,3S)-3-(4-chlorophenyl)oxiranyl]carbonyl]-](http://img.cochemist.com/ccimg/616900/616894-17-8.png)
![Pyrrolidine, 1-[[(2R,3S)-3-(4-chlorophenyl)oxiranyl]carbonyl]-](http://img.cochemist.com/ccimg/616900/616894-17-8_b.png)
![Phosphine oxide, bis[(1R)-1-phenylethyl][(1S)-1-phenylethyl]-, rel-](http://img.cochemist.com/ccimg/642500/642494-45-9.png)
![Phosphine oxide, bis[(1R)-1-phenylethyl][(1S)-1-phenylethyl]-, rel-](http://img.cochemist.com/ccimg/642500/642494-45-9_b.png)
![Morpholine, 4-[[(2R,3S)-3-(4-chlorophenyl)oxiranyl]carbonyl]-](http://img.cochemist.com/ccimg/616900/616894-14-5.png)
![Morpholine, 4-[[(2R,3S)-3-(4-chlorophenyl)oxiranyl]carbonyl]-](http://img.cochemist.com/ccimg/616900/616894-14-5_b.png)
![Tribenzo[3,4:5,6:7,8]cycloocta[1,2-c]pyridine, 7-methoxy-](http://img.cochemist.com/ccimg/874300/874204-60-1.png)
![Tribenzo[3,4:5,6:7,8]cycloocta[1,2-c]pyridine, 7-methoxy-](http://img.cochemist.com/ccimg/874300/874204-60-1_b.png)
![7-Oxabicyclo[2.2.1]hept-5-ene-2,3-diacetic acid, (1R,2S,3S,4S)-rel-](http://img.cochemist.com/ccimg/592600/592526-41-5.png)
![7-Oxabicyclo[2.2.1]hept-5-ene-2,3-diacetic acid, (1R,2S,3S,4S)-rel-](http://img.cochemist.com/ccimg/592600/592526-41-5_b.png)
![Acetamide, 2-bromo-N-[(4-methoxyphenyl)methyl]-N-2-propenyl-](http://img.cochemist.com/ccimg/686800/686777-71-9.png)
![Acetamide, 2-bromo-N-[(4-methoxyphenyl)methyl]-N-2-propenyl-](http://img.cochemist.com/ccimg/686800/686777-71-9_b.png)
![ETHANONE, 1-[(2R,3S)-3-(4-CHLOROPHENYL)OXIRANYL]-](http://img.cochemist.com/ccimg/463400/463309-25-3.png)
![ETHANONE, 1-[(2R,3S)-3-(4-CHLOROPHENYL)OXIRANYL]-](http://img.cochemist.com/ccimg/463400/463309-25-3_b.png)
![Ethanone, 1-[3'-(1,1-dimethylethyl)-2'-hydroxy[1,1'-biphenyl]-4-yl]-](http://img.cochemist.com/ccimg/521300/521273-05-2.png)
![Ethanone, 1-[3'-(1,1-dimethylethyl)-2'-hydroxy[1,1'-biphenyl]-4-yl]-](http://img.cochemist.com/ccimg/521300/521273-05-2_b.png)
![Phosphinic chloride, bis[(1S)-1-phenylethyl]-](http://img.cochemist.com/ccimg/425500/425407-73-4.png)
![Phosphinic chloride, bis[(1S)-1-phenylethyl]-](http://img.cochemist.com/ccimg/425500/425407-73-4_b.png)
![Phosphinic acid, bis[(1S)-1-phenylethyl]-](http://img.cochemist.com/ccimg/118400/118355-11-6.png)
![Phosphinic acid, bis[(1S)-1-phenylethyl]-](http://img.cochemist.com/ccimg/118400/118355-11-6_b.png)
![PHOSPHINIC AMIDE, P-[(1S)-1-PHENYLETHYL]-N,P-BIS[(1R)-1-PHENYLETHYL]-](http://img.cochemist.com/ccimg/643800/643726-35-6.png)
![PHOSPHINIC AMIDE, P-[(1S)-1-PHENYLETHYL]-N,P-BIS[(1R)-1-PHENYLETHYL]-](http://img.cochemist.com/ccimg/643800/643726-35-6_b.png)
![Benzeneethanamine, N-methyl-N-[(2E)-3-phenyl-2-propenyl]-](http://img.cochemist.com/ccimg/126500/126457-67-8.png)
![Benzeneethanamine, N-methyl-N-[(2E)-3-phenyl-2-propenyl]-](http://img.cochemist.com/ccimg/126500/126457-67-8_b.png)
![TRIBENZO[3,4:5,6:7,8]CYCLOOCTA[1,2-C]PYRIDINE](http://img.cochemist.com/ccimg/874300/874204-59-8.png)
![TRIBENZO[3,4:5,6:7,8]CYCLOOCTA[1,2-C]PYRIDINE](http://img.cochemist.com/ccimg/874300/874204-59-8_b.png)
![1H-PYRROLE, 1-[[(2R,3S)-3-[2-(8-PHENYLOCTYL)PHENYL]OXIRANYL]CARBONYL]-](http://img.cochemist.com/ccimg/880200/880175-80-4.png)
![1H-PYRROLE, 1-[[(2R,3S)-3-[2-(8-PHENYLOCTYL)PHENYL]OXIRANYL]CARBONYL]-](http://img.cochemist.com/ccimg/880200/880175-80-4_b.png)
![[1,1'-BIPHENYL]-2-OL, 4'-(DIMETHYLAMINO)-3-(1,1-DIMETHYLETHYL)-](http://img.cochemist.com/ccimg/624000/623941-47-9.png)
![[1,1'-BIPHENYL]-2-OL, 4'-(DIMETHYLAMINO)-3-(1,1-DIMETHYLETHYL)-](http://img.cochemist.com/ccimg/624000/623941-47-9_b.png)
![[1,1':3',1''-TERPHENYL]-2'-OL, 2,2'',5,5''-TETRAMETHYL-](http://img.cochemist.com/ccimg/624000/623941-64-0.png)
![[1,1':3',1''-TERPHENYL]-2'-OL, 2,2'',5,5''-TETRAMETHYL-](http://img.cochemist.com/ccimg/624000/623941-64-0_b.png)
![PHOSPHINE, TRIS[(1S)-1-PHENYLETHYL]-](http://img.cochemist.com/ccimg/642500/642494-51-7.png)
![PHOSPHINE, TRIS[(1S)-1-PHENYLETHYL]-](http://img.cochemist.com/ccimg/642500/642494-51-7_b.png)
![PHOSPHINIC AMIDE, N,P,P-TRIS[(1R)-1-PHENYLETHYL]-](http://img.cochemist.com/ccimg/643800/643726-37-8.png)
![PHOSPHINIC AMIDE, N,P,P-TRIS[(1R)-1-PHENYLETHYL]-](http://img.cochemist.com/ccimg/643800/643726-37-8_b.png)
![[1,1'-BIPHENYL]-2-OL, 3-(1,1-DIMETHYLETHYL)-2',5'-DIMETHYL-](http://img.cochemist.com/ccimg/521300/521273-08-5.png)
![[1,1'-BIPHENYL]-2-OL, 3-(1,1-DIMETHYLETHYL)-2',5'-DIMETHYL-](http://img.cochemist.com/ccimg/521300/521273-08-5_b.png)
![[1,1'-BIPHENYL]-2-OL, 3,5-BIS(1,1-DIMETHYLETHYL)-4'-METHOXY-](http://img.cochemist.com/ccimg/521300/521273-06-3.png)
![[1,1'-BIPHENYL]-2-OL, 3,5-BIS(1,1-DIMETHYLETHYL)-4'-METHOXY-](http://img.cochemist.com/ccimg/521300/521273-06-3_b.png)
![OXIRANECARBOXAMIDE, N,N-DIETHYL-3-[2-(8-PHENYLOCTYL)PHENYL]-, (2R,3S)-](http://img.cochemist.com/ccimg/463400/463308-92-1.png)
![OXIRANECARBOXAMIDE, N,N-DIETHYL-3-[2-(8-PHENYLOCTYL)PHENYL]-, (2R,3S)-](http://img.cochemist.com/ccimg/463400/463308-92-1_b.png)
![2-Propyn-1-one, 3-phenyl-1-[4-(phenylethynyl)phenyl]-](http://img.cochemist.com/ccimg/850000/849941-88-4.png)
![2-Propyn-1-one, 3-phenyl-1-[4-(phenylethynyl)phenyl]-](http://img.cochemist.com/ccimg/850000/849941-88-4_b.png)
![2-Propyn-1-one, 3-[(1,1-dimethylethyl)dimethylsilyl]-1-phenyl-](http://img.cochemist.com/ccimg/850000/849941-86-2.png)
![2-Propyn-1-one, 3-[(1,1-dimethylethyl)dimethylsilyl]-1-phenyl-](http://img.cochemist.com/ccimg/850000/849941-86-2_b.png)
![[Pt(bicyclo[2.2.1]hept-2-en)3]](http://img.cochemist.com/ccimg/57200/57158-98-2.png)
![[Pt(bicyclo[2.2.1]hept-2-en)3]](http://img.cochemist.com/ccimg/57200/57158-98-2_b.png)
![Acetic acid, [ethyl(1-methylethyl)amino]oxo-, methyl ester](http://img.cochemist.com/ccimg/850000/849941-92-0.png)
![Acetic acid, [ethyl(1-methylethyl)amino]oxo-, methyl ester](http://img.cochemist.com/ccimg/850000/849941-92-0_b.png)
![Aziridine, 1-[(4-methylphenyl)sulfonyl]-2,3-diphenyl-, cis-](http://img.cochemist.com/ccimg/17900/17879-98-0.png)
![Aziridine, 1-[(4-methylphenyl)sulfonyl]-2,3-diphenyl-, cis-](http://img.cochemist.com/ccimg/17900/17879-98-0_b.png)
![Methanone, [(2R,3S)-3-(4-chlorophenyl)oxiranyl]phenyl-](http://img.cochemist.com/ccimg/61900/61840-96-8.png)
![Methanone, [(2R,3S)-3-(4-chlorophenyl)oxiranyl]phenyl-](http://img.cochemist.com/ccimg/61900/61840-96-8_b.png)
![2-Propenoic acid, 2-[bis[(1,1-dimethylethoxy)carbonyl]amino]-, methylester](http://img.cochemist.com/ccimg/201400/201338-62-7.png)
![2-Propenoic acid, 2-[bis[(1,1-dimethylethoxy)carbonyl]amino]-, methylester](http://img.cochemist.com/ccimg/201400/201338-62-7_b.png)
![Aziridine, 1-[(4-methylphenyl)sulfonyl]-2,3-diphenyl-, trans-](http://img.cochemist.com/ccimg/17900/17879-99-1.png)
![Aziridine, 1-[(4-methylphenyl)sulfonyl]-2,3-diphenyl-, trans-](http://img.cochemist.com/ccimg/17900/17879-99-1_b.png)
![Palladium,bis[2-[[bis[2,4-bis(1,1-dimethylethyl)phenoxy]phosphino-kP]oxy]-3,5-bis(1,1-dimethylethyl)phenyl-kC]di-m-chlorodi-, stereoisomer](http://img.cochemist.com/ccimg/217200/217189-40-7.png)
![Palladium,bis[2-[[bis[2,4-bis(1,1-dimethylethyl)phenoxy]phosphino-kP]oxy]-3,5-bis(1,1-dimethylethyl)phenyl-kC]di-m-chlorodi-, stereoisomer](http://img.cochemist.com/ccimg/217200/217189-40-7_b.png)
![1,3-Propanediamine, N,N'-bis[2,6-bis(1-methylethyl)phenyl]-](http://img.cochemist.com/ccimg/173200/173163-37-6.png)
![1,3-Propanediamine, N,N'-bis[2,6-bis(1-methylethyl)phenyl]-](http://img.cochemist.com/ccimg/173200/173163-37-6_b.png)
![2-Butyn-1-one, 4-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1-phenyl-](http://img.cochemist.com/ccimg/81600/81535-84-4.png)
![2-Butyn-1-one, 4-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1-phenyl-](http://img.cochemist.com/ccimg/81600/81535-84-4_b.png)
![bis[(2,3,5,6-η)-bicyclo[2.2.1]hepta-2,5-diene]di-μ-chlorodirhodium](http://img.cochemist.com/ccimg/12300/12257-42-0.png)
![bis[(2,3,5,6-η)-bicyclo[2.2.1]hepta-2,5-diene]di-μ-chlorodirhodium](http://img.cochemist.com/ccimg/12300/12257-42-0_b.png)
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