Co-reporter:Katie J. Emery;Tell Tuttle
Organic & Biomolecular Chemistry 2017 vol. 15(Issue 4) pp:920-927
Publication Date(Web):2017/01/25
DOI:10.1039/C6OB02684B
A recent paper identified a series of alternative cyclisation pathways of aryl radicals that resulted from electron transfer to various tethered haloarene–acetylarene substrates, in either benzene or DMSO as solvent. The electron transfer occurred from one of two enolates that were formed in the presence of KOtBu: either the enolate of the acetylarene, within the haloarene–acetylarene substrate, or the enolate 7 of the N,N′-dipropyl diketopiperazine (DKP) additive 6. This paper uses contemporary computational methods to determine the reaction pathways involved; depending on the substrate, the aryl radical underwent (i) SRN1 onto the enolate anion of the acetylarene, (ii) aryl–aryl bond formation, (iii) tandem hydrogen atom abstraction followed by SRN1 cyclisation and even (iv) ArC–N cleavage. The influence of the solvent was investigated. In this paper it is shown that the solvent influences which reactive species are present in the reaction mixture, and whether each species acts as an electron donor or an electron acceptor in the radical initiation or propagation steps. The main initiation step is a single electron transfer from the enolate anion 7 of the DKP additive in benzene, but in DMSO the initiation can occur from the enolate anion of the substrate itself. Using computational techniques a deeper understanding of the radical pathways involved has been obtained, which shows how we can use solvent to preferentially access products arising from either SRN1 or aryl–aryl bond formation pathways.
Co-reporter:Katie J. Emery;Tell Tuttle
Organic & Biomolecular Chemistry 2017 vol. 15(Issue 41) pp:8810-8819
Publication Date(Web):2017/10/25
DOI:10.1039/C7OB02209C
A designed N,N′-dialkyldiketopiperazine (DKP) provides evidence for the role of DKP additives as initiators that act by electron transfer in base-induced homolytic aromatic substitution reactions, involving coupling of haloarenes to arenes.
Co-reporter:Florimond Cumine;Shengze Zhou;Tell Tuttle
Organic & Biomolecular Chemistry 2017 vol. 15(Issue 15) pp:3324-3336
Publication Date(Web):2017/04/11
DOI:10.1039/C7OB00036G
Several diketopiperazines have been shown to promote carbon–carbon coupling between benzene and aryl halides in the presence of potassium tert-butoxide and without the assistance of a transition metal catalyst. The structure of the diketopiperazine has an influence on its reductive potential and can help to promote the coupling of the more challenging aryl bromides with benzene.
Co-reporter:Andrew J. Smith;Allan Young;Simon Rohrbach;Erin F. O'Connor;Mark Allison;Hong-Shuang Wang;Dr. Darren L. Poole;Dr. Tell Tuttle; Dr. John A. Murphy
Angewandte Chemie 2017 Volume 129(Issue 44) pp:13935-13939
Publication Date(Web):2017/10/23
DOI:10.1002/ange.201707914
AbstractRecent studies by Stoltz, Grubbs et al. have shown that triethylsilane and potassium tert-butoxide react to form a highly attractive and versatile system that shows (reversible) silylation of arenes and heteroarenes as well as reductive cleavage of C−O bonds in aryl ethers and C−S bonds in aryl thioethers. Their extensive mechanistic studies indicate a complex network of reactions with a number of possible intermediates and mechanisms, but their reactions likely feature silyl radicals undergoing addition reactions and SH2 reactions. This paper focuses on the same system, but through computational and experimental studies, reports complementary facets of its chemistry based on a) single-electron transfer (SET), and b) hydride delivery reactions to arenes.
Co-reporter:Florimond Cumine;Allan Young;Hans-Ulrich Reissig;Tell Tuttle
European Journal of Organic Chemistry 2017 Volume 2017(Issue 46) pp:6867-6871
Publication Date(Web):2017/12/15
DOI:10.1002/ejoc.201701381
Computational studies have been performed on potassium alkoxide-allenes, as well as potassium and lithium amido-allenes to probe the mechanism of their cyclizations to dihydrofurans and to 2,5-dihydropyrroles. A long-standing proposal envisaged electron transfer from dimsyl anions (formed by deprotonation of the solvent DMSO) but this pathway shows an exceptionally high kinetic barrier, while direct 5-endo-trig cyclization of the alkoxides and amides is much more easily achievable. The energy profiles for 4-exo-trig cyclizations onto the allenes are also explored, and the preferred formation of the observed five-membered products is rationalized.
Co-reporter:Joshua P. Barham; Graeme Coulthard; Katie J. Emery; Eswararao Doni; Florimond Cumine; Giuseppe Nocera; Matthew P. John; Leonard E. A. Berlouis; Thomas McGuire; Tell Tuttle
Journal of the American Chemical Society 2016 Volume 138(Issue 23) pp:7402-7410
Publication Date(Web):May 16, 2016
DOI:10.1021/jacs.6b03282
Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes, and SRN1 reactions. Direct electron transfer would imply that alkali metal alkoxides are willing partners in these electron transfer reactions, but the literature reports provide little or no experimental evidence for this. This paper examines each of these classes of reaction in turn, and contests the roles proposed for KOtBu; instead, it provides new mechanistic information that in each case supports the in situ formation of organic electron donors. We go on to show that direct electron transfer from KOtBu can however occur in appropriate cases, where the electron acceptor has a reduction potential near the oxidation potential of KOtBu, and the example that we use is CBr4. In this case, computational results support electrochemical data in backing a direct electron transfer reaction.
Co-reporter:Joshua P. Barham, Matthew P. John, and John A. Murphy
Journal of the American Chemical Society 2016 Volume 138(Issue 47) pp:15482-15487
Publication Date(Web):November 3, 2016
DOI:10.1021/jacs.6b09690
We report a simple one-pot protocol that affords functionalization of N-CH3 groups in N-methyl-N,N-dialkylamines with high selectivity over N-CH2R or N-CHR2 groups. The radical cation DABCO+•, prepared in situ by oxidation of DABCO with a triarylaminium salt, effects highly selective and contra-thermodynamic C–H abstraction from N-CH3 groups. The intermediates that result react in situ with organometallic nucleophiles in a single pot, affording novel and highly selective homologation of N-CH3 groups. Chemoselectivity, scalability, and recyclability of reagents are demonstrated, and a mechanistic proposal is corroborated by computational and experimental results. The utility of the transformation is demonstrated in the late-stage site-selective functionalization of natural products and pharmaceuticals, allowing rapid derivatization for investigation of structure–activity relationships.
Co-reporter:Greg M. Anderson, Iain Cameron, John A. Murphy and Tell Tuttle
RSC Advances 2016 vol. 6(Issue 14) pp:11335-11343
Publication Date(Web):18 Jan 2016
DOI:10.1039/C5RA26483A
The utilization of computational methods to predict reactivity is an increasingly useful tool for chemists to save time and materials by screening compounds for desirable reactivity prior to testing in the laboratory. In the field of electron transfer reactions, screening can be performed through the application of Marcus Hush theory to calculate the activation free energy of any potential reaction. This work describes the most accurate and efficient approach for modelling the electron transfer process. In particular, the importance of using an electron transfer complex to model these reactions rather than considering donor and acceptor molecules as separate entities is highlighted. The use of the complex model is found to produce more accurate calculation of the electron transfer energy when the donor and acceptor spin densities are adequately localised.
Co-reporter:Katie J. Emery, Tell Tuttle, Alan R. Kennedy, John A. Murphy
Tetrahedron 2016 Volume 72(Issue 48) pp:7875-7887
Publication Date(Web):1 December 2016
DOI:10.1016/j.tet.2016.05.083
Under basic conditions aryl halides can undergo SRN1 reactions, BHAS reactions and benzyne formations. Appropriate complex substrates afford an opportunity to study inherent selectivities. SRN1 reactions are usually favoured under photoactivated conditions, but this paper reports their success using ground-state and transition metal-free conditions. In benzene, the enolate salt 12, derived by deprotonation of diketopiperazine 11, behaves as an electron donor, and assists the initiation of the reactions, but in DMSO, it is not required. The outcomes are compared and contrasted with a recent photochemical study on similar substrates. A particular difference is the prevalence of hydride shuttle reactions under relatively mild thermal conditions.Figure optionsDownload full-size imageDownload high-quality image (135 K)Download as PowerPoint slide
Co-reporter:Joshua P. Barham;Dr. Graeme Coulthard;Ryan G. Kane;Nathan Delgado;Dr. Matthew P. John;Dr. John A. Murphy
Angewandte Chemie International Edition 2016 Volume 55( Issue 14) pp:4492-4496
Publication Date(Web):
DOI:10.1002/anie.201511847
Abstract
Transition metal-free couplings of haloarenes with arenes, triggered by the use of alkali metal alkoxides in the presence of an organic additive, are receiving significant attention in the literature. Most of the known organic additives effect coupling of iodoarenes, but not bromoarenes, to arenes. Recently it was reported that 2-pyridinecarbinol (11) extends the reaction to aryl bromides. This paper investigates the mechanism, and reports evidence for dianions derived from 11 as electron donors to initiate the reaction. It also proposes routes by which electron-poor benzoyl derivatives can be transformed into electron donors to initiate these reactions.
Co-reporter:Joshua P. Barham;Dr. Graeme Coulthard;Ryan G. Kane;Nathan Delgado;Dr. Matthew P. John;Dr. John A. Murphy
Angewandte Chemie 2016 Volume 128( Issue 14) pp:4568-4572
Publication Date(Web):
DOI:10.1002/ange.201511847
Abstract
Transition metal-free couplings of haloarenes with arenes, triggered by the use of alkali metal alkoxides in the presence of an organic additive, are receiving significant attention in the literature. Most of the known organic additives effect coupling of iodoarenes, but not bromoarenes, to arenes. Recently it was reported that 2-pyridinecarbinol (11) extends the reaction to aryl bromides. This paper investigates the mechanism, and reports evidence for dianions derived from 11 as electron donors to initiate the reaction. It also proposes routes by which electron-poor benzoyl derivatives can be transformed into electron donors to initiate these reactions.
Co-reporter:Samuel S. Hanson;Dr. Eswararao Doni;Kyle T. Traboulsee;Dr. Graeme Coulthard;Dr. John A. Murphy;Dr. C. Adam Dyker
Angewandte Chemie 2015 Volume 127( Issue 38) pp:11388-11391
Publication Date(Web):
DOI:10.1002/ange.201505378
Abstract
A new ground-state organic electron donor has been prepared that features four strongly π-donating iminophosphorano substituents on a bispyridinylidene skeleton. Cyclic voltammetry reveals a record redox potential of −1.70 V vs. saturated calomel electrode (SCE) for the couple involving the neutral organic donor and its dication. This highly reducing organic compound can be isolated (44 %) or more conveniently generated in situ by a deprotonation reaction involving its readily prepared pyridinium ion precursor. This donor is able to reduce a variety of aryl halides, and, owing to its redox potential, was found to be the first organic donor to be effective in the thermally induced reductive SN bond cleavage of N,N-dialkylsulfonamides, and reductive hydrodecyanation of malonitriles.
Co-reporter:Samuel S. Hanson;Dr. Eswararao Doni;Kyle T. Traboulsee;Dr. Graeme Coulthard;Dr. John A. Murphy;Dr. C. Adam Dyker
Angewandte Chemie International Edition 2015 Volume 54( Issue 38) pp:11236-11239
Publication Date(Web):
DOI:10.1002/anie.201505378
Abstract
A new ground-state organic electron donor has been prepared that features four strongly π-donating iminophosphorano substituents on a bispyridinylidene skeleton. Cyclic voltammetry reveals a record redox potential of −1.70 V vs. saturated calomel electrode (SCE) for the couple involving the neutral organic donor and its dication. This highly reducing organic compound can be isolated (44 %) or more conveniently generated in situ by a deprotonation reaction involving its readily prepared pyridinium ion precursor. This donor is able to reduce a variety of aryl halides, and, owing to its redox potential, was found to be the first organic donor to be effective in the thermally induced reductive SN bond cleavage of N,N-dialkylsulfonamides, and reductive hydrodecyanation of malonitriles.
Co-reporter:Shengze Zhou ; Eswararao Doni ; Greg M. Anderson ; Ryan G. Kane ; Scott W. MacDougall ; Victoria M. Ironmonger ; Tell Tuttle
Journal of the American Chemical Society 2014 Volume 136(Issue 51) pp:17818-17826
Publication Date(Web):December 4, 2014
DOI:10.1021/ja5101036
Coupling of haloarenes to arenes has been facilitated by a diverse range of organic additives in the presence of KOtBu or NaOtBu since the first report in 2008. Very recently, we showed that the reactivity of some of these additives (e.g., compounds 6 and 7) could be explained by the formation of organic electron donors in situ, but the role of other additives was not addressed. The simplest of these, alcohols, including 1,2-diols, 1,2-diamines, and amino acids are the most intriguing, and we now report experiments that support their roles as precursors of organic electron donors, underlining the importance of this mode of initiation in these coupling reactions.
Co-reporter:Shengze Zhou, Greg M. Anderson, Bhaskar Mondal, Eswararao Doni, Vicki Ironmonger, Michael Kranz, Tell Tuttle and John A. Murphy
Chemical Science 2014 vol. 5(Issue 2) pp:476-482
Publication Date(Web):09 Oct 2013
DOI:10.1039/C3SC52315B
Recent papers report transition metal-free couplings of haloarenes to arenes to form biaryls, triggered by alkali metal tert-butoxides in the presence of various additives. These reactions proceed through radical intermediates, but understanding the origin of the radicals has been problematic. Electron transfer from a complex formed from potassium tert-butoxide with additives, such as phenanthroline, has been suggested to initiate the radical process. However, our computational results encouraged us to search for alternatives. We report that heterocycle-derived organic electron donors achieve the coupling reactions and these donors can form in situ in the above cases. We show that an electron transfer route can operate either with phenanthrolines as additives or using pyridine as solvent, and we propose new heterocyclic structures for the respective electron donors involved in these cases. In the absence of additives, the coupling reactions are still successful, although more sluggish, and in those cases benzynes are proposed to play crucial roles in the initiation process.
Co-reporter:Eswararao Doni and John A. Murphy
Chemical Communications 2014 vol. 50(Issue 46) pp:6073-6087
Publication Date(Web):25 Mar 2014
DOI:10.1039/C3CC48969H
In recent times, metal-free chemistry has received significant attention due to its inherent qualities and its potential savings in the costs of (i) reagents and (ii) environmental treatments of residues. In this context, recently developed neutral organic electron-donors have shown an ability to perform challenging reductions that are traditionally the preserve of reactive metals and metal-based complexes, under mild reaction conditions. Hence, this feature article is aimed at describing the evolution of neutral organic super-electron-donors and their rapidly developing applications in electron-transfer reactions.
Co-reporter:Steven O'Sullivan;Eswararao Doni;Dr. Tell Tuttle;Dr. John A. Murphy
Angewandte Chemie International Edition 2014 Volume 53( Issue 2) pp:474-478
Publication Date(Web):
DOI:10.1002/anie.201306543
Abstract
A photoactivated neutral organic super electron donor cleaves challenging arenesulfonamides derived from dialkylamines at room temperature. It also cleaves a) ArCNR and b) ArNC bonds. This study also highlights the assistance given to these cleavage reactions by the groups attached to N in (a) and to C in (b), by lowering LUMO energies and by stabilizing the products of fragmentation.
Co-reporter:John A. Murphy
The Journal of Organic Chemistry 2014 Volume 79(Issue 9) pp:3731-3746
Publication Date(Web):March 7, 2014
DOI:10.1021/jo500071u
Based on simple ideas of electron-rich alkenes, exemplified by tetrakis(dimethylamino)ethene, TDAE, and on additional driving force associated with aromatization, families of very powerful neutral organic super-electron-donors (SEDs) have been developed. In the ground state, they carry out metal-free reductions of a range of functional groups. Iodoarenes are reduced either to aryl radicals or, with stronger donors, to aryl anions. Reduction to aryl radicals allows the initiation of very efficient transition-metal-free coupling of haloarenes to arenes. The donors also reduce alkyl halides, arenesulfonamides, triflates, and triflamdes, Weinreb amides, and acyloin derivatives. Under photoactivation at 365 nm, they are even more powerful and reductively cleave aryl chlorides. They reduce unactivated benzenes to the corresponding radical anions and display original selectivities in preferentially reducing benzenes over malonates or cyanoacetates. Additionally, they reductively cleave ArC–X, ArX–C (X = N or O) and ArC–C bonds, provided that the two resulting fragments are somewhat stabilized.
Co-reporter:Eswararao Doni ; Bhaskar Mondal ; Steven O’Sullivan ; Tell Tuttle
Journal of the American Chemical Society 2013 Volume 135(Issue 30) pp:10934-10937
Publication Date(Web):July 16, 2013
DOI:10.1021/ja4050168
The prevalence of metal-based reducing reagents, including metals, metal complexes, and metal salts, has produced an empirical order of reactivity that governs our approach to chemical synthesis. However, this reactivity may be influenced by stabilization of transition states, intermediates, and products through substrate–metal bonding. This article reports that in the absence of such stabilizing interactions, established chemoselectivities can be overthrown. Thus, photoactivation of the recently developed neutral organic superelectron donor 5 selectively reduces alkyl-substituted benzene rings in the presence of activated esters and nitriles, in direct contrast to metal-based reductions, opening a new perspective on reactivity. The altered outcomes arising from the organic electron donors are attributed to selective interactions between the neutral organic donors and the arene rings of the substrates.
Co-reporter:Hardeep S. Farwaha, Götz Bucher and John A. Murphy
Organic & Biomolecular Chemistry 2013 vol. 11(Issue 46) pp:8073-8081
Publication Date(Web):11 Oct 2013
DOI:10.1039/C3OB41701H
Tricyclic donor 26 has been prepared and is the most reducing neutral ground-state organic molecule known, with an oxidation potential 260 mV more negative than the previous record. Cyclic voltammetry shows that a 2-electron reversible redox process occurs in DMF as solvent at −1.46 V vs. Ag/AgCl.
Co-reporter:Eswararao Doni;Steven O'Sullivan ;Dr. John A. Murphy
Angewandte Chemie International Edition 2013 Volume 52( Issue 8) pp:2239-2242
Publication Date(Web):
DOI:10.1002/anie.201208066
Co-reporter:Eswararao Doni;Steven O'Sullivan ;Dr. John A. Murphy
Angewandte Chemie 2013 Volume 125( Issue 8) pp:2295-2298
Publication Date(Web):
DOI:10.1002/ange.201208066
Co-reporter:Phillip I. Jolly, Shengze Zhou, Douglas W. Thomson, Jean Garnier, John A. Parkinson, Tell Tuttle and John A. Murphy
Chemical Science 2012 vol. 3(Issue 5) pp:1675-1679
Publication Date(Web):14 Feb 2012
DOI:10.1039/C2SC20054F
Previous efforts to prepare tetraazafulvalenes derived from imidazolium salt precursors have met with little success (one anomalously favourable example is known), and this is in line with the predicted reactivity of these compounds. However, we now report the preparation of a series of these tetraazafulvalenes formed either by deprotonation of 1,3-dialkylimidazolium salts or by Birch reduction of biimidazolium salts. The tetraazafulvalenes are highly reactive; for example, they act as Super-Electron-Donors towards iodoarenes. The two most reactive examples are formed more efficiently by Birch reduction than by the deprotonation route. Nevertheless, even in cases where the deprotonation approach affords a low stationary concentration, the mixture of precursor salt and base still produces the same powerful reductive chemistry that is the hallmark of tetraazafulvalene electron donors.
Co-reporter:Luka S. Kovacevic;Christopher Idziak;Augustinas Markevicius;Callum Scullion;Michael J. Corr;Dr. Alan R. Kennedy;Dr. Tell Tuttle;Dr. John A. Murphy
Angewandte Chemie International Edition 2012 Volume 51( Issue 34) pp:8516-8519
Publication Date(Web):
DOI:10.1002/anie.201202990
Co-reporter:Elise Cahard;Dr. Franziska Schoenebeck;Jean Garnier;Sylvain P. Y. Cutulic;Dr. Shengze Zhou;Dr. John A. Murphy
Angewandte Chemie International Edition 2012 Volume 51( Issue 15) pp:3673-3676
Publication Date(Web):
DOI:10.1002/anie.201200084
Co-reporter:Michael J. Corr and John A. Murphy
Chemical Society Reviews 2011 vol. 40(Issue 5) pp:2279-2292
Publication Date(Web):01 Mar 2011
DOI:10.1039/C0CS00150C
Hydrogenases catalyse redox reactions with molecular hydrogen, either as substrate or product. The enzymes harness hydrogen as a reductant using metals that are abundant and economical, namely, nickel and iron, and should provide new pointers for the economic use of hydrogen in manmade devices. The most recently discovered and perhaps the most enigmatic of the hydrogenases is the [Fe]-hydrogenase, used by certain microorganisms in the pathway that reduces carbon dioxide to methane. Since its discovery some twenty years ago, [Fe]-hydrogenase has consistently provided structural and mechanistic surprises, often requiring complete re-evaluation of its mechanism of action. This tutorial review combines recent advances in X-ray crystallography and other analytical techniques, as well as in computational studies and in chemical synthesis to provide a platform for understanding this remarkable enzyme type.
Co-reporter:Ryan Sword, Luke A. Baldwin and John A. Murphy
Organic & Biomolecular Chemistry 2011 vol. 9(Issue 9) pp:3560-3570
Publication Date(Web):22 Feb 2011
DOI:10.1039/C0OB01282C
Reactions of super-electron-donors (SEDs) derived from 4-dimethylaminopyridine and from N-methylbenzimidazole with α-methoxy-γ-alkoxyalkyl iodides lead to liberation of the γ-alkoxy groups as their alcohols. This is consistent with generation of alkyl radicals from the alkyl halide precursors, and trapping of these radicals by the radical-cation of the SED, followed by a heterolytic fragmentation.
Co-reporter:Neil J. Findlay ; Stuart R. Park ; Franziska Schoenebeck ; Elise Cahard ; Sheng-ze Zhou ; Leonard E. A. Berlouis ; Mark D. Spicer ; Tell Tuttle
Journal of the American Chemical Society 2010 Volume 132(Issue 44) pp:15462-15464
Publication Date(Web):October 20, 2010
DOI:10.1021/ja107703n
The first crown-tetracarbene complex of Ni(II) has been prepared, and its crystal structure determined. The complex can be reduced by Na/Hg, with an uptake of two electrons. The reduced complex reductively cleaves arenesulfonamides, including those derived from secondary aliphatic amines, and effects Birch reduction of anthracenes as well as reductive cleavage of stilbene oxides. Computational studies show that the orbital that receives electrons upon reduction of the complex 2 is predominantly based on the crown carbene ligand and also that the HOMO of the parent complex 2 is based on the ligand.
Co-reporter:Michael J. Corr ; Mark D. Roydhouse ; Kirsty F. Gibson ; Sheng-ze Zhou ; Alan R. Kennedy
Journal of the American Chemical Society 2009 Volume 131(Issue 49) pp:17980-17985
Publication Date(Web):November 16, 2009
DOI:10.1021/ja908191k
2-Dimethylalkylammonium pyridinium and 2-dimethylalkylammonium pyrimidinium ditriflate salts are very powerful methylating agents toward phosphorus (triphenylphosphine) and nitrogen (triethylamine) nucleophiles. In competition experiments with triethylamine as nucleophile, these N-methyl disalts are more reactive methylating agents than dimethyl sulfate. Reaction of the pyridinium dications with water as an oxygen nucleophile leads to attack at the 2-position of the heteroaromatic ring and displacement of an ammonium group; 2-hydroxypyridinium compounds are formed in the first instance, which are easily converted to 2-pyridones. Extending the scope of the reactions, a tricationic 2,6-bis(dimethylalkylammonium)pyridinium salt has also been prepared and characterized and its reactivity as a methylating agent assessed in comparison with that of the dications.
Co-reporter:Michael J. Corr ; Kirsty F. Gibson ; Alan R. Kennedy
Journal of the American Chemical Society 2009 Volume 131(Issue 26) pp:9174-9175
Publication Date(Web):June 17, 2009
DOI:10.1021/ja9035847
This commmunication demonstrates the preparation, isolation, and full characterization of superelectrophilic salts based on amidine dications in organic solvent, as their triflate salts. These dications are highly activated toward regiospecific reaction with hydrogen gas under mild conditions in the presence of a metal catalyst (Pd/C), mimicking the behavior of the natural substrate, N5,N10-methenyltetrahydromethanopterin, in the iron−sulfur cluster-free [Fe]-hydrogenase.
Co-reporter:Kevin Hisler, Aurélien G.J. Commeureuc, Sheng-ze Zhou, John A. Murphy
Tetrahedron Letters 2009 50(26) pp: 3290-3293
Publication Date(Web):
DOI:10.1016/j.tetlet.2009.02.060
Co-reporter:Stuart R. Park, Neil J. Findlay, Jean Garnier, Shengze Zhou, Mark D. Spicer, John A. Murphy
Tetrahedron 2009 65(52) pp: 10756-10761
Publication Date(Web):
DOI:10.1016/j.tet.2009.10.090
Co-reporter:Ross McKie;John A. Murphy Dr.;Stuart R. Park;Mark D. Spicer Dr.;Sheng-ze Zhou Dr.
Angewandte Chemie International Edition 2007 Volume 46(Issue 34) pp:
Publication Date(Web):23 JUL 2007
DOI:10.1002/anie.200702138
Two ways about it: The first metal N-heterocyclic carbene complexes derived from a cyclic tetraimidazolium salt show a remarkable versatility of ligand conformation and coordination geometry. With PdII, a mononuclear square-planar complex is obtained, but with CuI and AgI, an unprecedented dinuclear motif with a short metal–metal interaction is observed (see structure; N blue, C white ellipsoids, H white circles).
Co-reporter:John A. Murphy Dr.;Sheng-ze Zhou Dr.;Douglas W. Thomson;Franziska Schoenebeck;Mohan Mahesh Dr.;Stuart R. Park;Tell Tuttle Dr.;Leonard E. A. Berlouis Dr.
Angewandte Chemie International Edition 2007 Volume 46(Issue 27) pp:
Publication Date(Web):4 JUN 2007
DOI:10.1002/anie.200700554
It takes two to cyclize: Aryl halides are reduced to aryl anions by double electron transfer from the neutral ground-state electron donor 1 (see scheme), as shown by the formation of a cyclic ketone (2). The reduced compound (3) is also formed. Calculations show that the loss of two electrons from 1 is both thermodynamically and kinetically viable and generates a more planar resonance-stabilized structure.
Co-reporter:John A. Murphy Dr.;Sheng-ze Zhou Dr.;Douglas W. Thomson;Franziska Schoenebeck;Mohan Mahesh Dr.;Stuart R. Park;Tell Tuttle Dr.;Leonard E. A. Berlouis Dr.
Angewandte Chemie 2007 Volume 119(Issue 27) pp:
Publication Date(Web):4 JUN 2007
DOI:10.1002/ange.200700554
Zum Cyclisieren braucht es zwei: Arylhalogenide werden durch doppelten Elektronentransfer vom Elektronendonor 1 mit neutralem Grundzustand zu Arylanionen reduziert (siehe Schema), wie die Bildung eines cyclischen Ketons (2) belegt. Daneben entsteht die reduzierte Verbindung 3. Rechnungen zufolge ist die Abgabe zweier Elektronen von 1 sowohl thermodynamisch als auch kinetisch möglich und liefert eine planare, resonanzstabilisierte Struktur.
Co-reporter:Ross McKie;John A. Murphy Dr.;Stuart R. Park;Mark D. Spicer Dr.;Sheng-ze Zhou Dr.
Angewandte Chemie 2007 Volume 119(Issue 34) pp:
Publication Date(Web):23 JUL 2007
DOI:10.1002/ange.200702138
Auf zweierlei Weise: Der erste Metallkomplex eines N-heterocyclischen Carbens, das aus einem cyclischen Tetraimidazoliumsalz entsteht, hat eine bemerkenswert flexible Ligandenkonformation und Koordinationsgeometrie. Mit PdII erhält man einen quadratisch-planar koordinierten Einkernkomplex, mit CuI und AgI hingegen eine neuartige Zweikernstruktur mit kleinem Metall-Metall-Abstand (siehe Struktur; N blau, C weiße Ellipsoide, H weiße Kugeln).
Co-reporter:S. Lang and J. A. Murphy
Chemical Society Reviews 2006 vol. 35(Issue 2) pp:146-156
Publication Date(Web):23 Nov 2005
DOI:10.1039/B505080D
The azide group has a diverse and extensive role in organic chemistry, reflected in the power of azide anion as a strong nucleophile, the role of organic azides as excellent substrates for cycloaddition reactions, the uses of azides as precursors of amines and nitrenes, and azide rearrangements known as the Curtius and Schmidt reactions. In recent years the scope of the Schmidt reaction has begun to be explored in depth, so that it now represents an important reaction in synthetic chemistry. This tutorial review analyses and summarises key recent developments in the field of Schmidt reactions.
Co-reporter:John A. Murphy Dr.;Tanweer A. Khan Dr.;Sheng-ze Zhou Dr.;Douglas W. Thomson;Mohan Mahesh
Angewandte Chemie 2005 Volume 117(Issue 9) pp:
Publication Date(Web):26 JAN 2005
DOI:10.1002/ange.200462038
Elektronentransfer-Reduktionen nichtaktivierter Aryl- und Alkyliodide mit einer neutralen organischen Verbindung im Grundzustand werden beschrieben. Das Reduktionsmittel 1 ist in zwei Stufen aus N-Methylbenzimidazol zugänglich. Die Reaktion mit einem Iodalkan oder -aren liefert dann cyclisierte Produkte (siehe Schema).
Co-reporter:John A. Murphy Dr.;Tanweer A. Khan Dr.;Sheng-ze Zhou Dr.;Douglas W. Thomson;Mohan Mahesh
Angewandte Chemie International Edition 2005 Volume 44(Issue 9) pp:
Publication Date(Web):26 JAN 2005
DOI:10.1002/anie.200462038
Electron-transfer reductions of unactivated aryl and alkyl iodides with a neutral ground-state organic molecule are reported. The reducing agent 1 is formed in two steps from N-methylbenzimidazole using very simple chemistry, and subsequent treatment of the iodoalkane or -arene with 1 affords cyclized products (see scheme).
Co-reporter:Dimitrios E. Lizos and John A. Murphy
Organic & Biomolecular Chemistry 2003 vol. 1(Issue 1) pp:117-122
Publication Date(Web):29 Nov 2002
DOI:10.1039/B208114H
A brief, efficient and economical synthesis of the spiropyrrolidinyloxindoles, horsfiline and coerulescine, has been achieved, starting from itaconic acid and, respectively, p-anisidine or o-iodoaniline. Tandem radical cyclisation of iodoaryl alkenyl azides is the key step in both syntheses.
Co-reporter:Nadeem Bashir and John A. Murphy
Chemical Communications 2000 (Issue 7) pp:627-628
Publication Date(Web):22 Mar 2000
DOI:10.1039/B000786M
Trapping of secondary alkyl radicals with tetrathiafulvalenium
tetrafluoroborate (TTF+·BF4−)
leads to S-alkyltetrathiafulvalenium tetrafluoroborate salts; the
solvolysis of such salts is critically dependent on the presence of
appropriately sited neighbouring groups.
Co-reporter:Shengze Zhou, Greg M. Anderson, Bhaskar Mondal, Eswararao Doni, Vicki Ironmonger, Michael Kranz, Tell Tuttle and John A. Murphy
Chemical Science (2010-Present) 2014 - vol. 5(Issue 2) pp:NaN482-482
Publication Date(Web):2013/10/09
DOI:10.1039/C3SC52315B
Recent papers report transition metal-free couplings of haloarenes to arenes to form biaryls, triggered by alkali metal tert-butoxides in the presence of various additives. These reactions proceed through radical intermediates, but understanding the origin of the radicals has been problematic. Electron transfer from a complex formed from potassium tert-butoxide with additives, such as phenanthroline, has been suggested to initiate the radical process. However, our computational results encouraged us to search for alternatives. We report that heterocycle-derived organic electron donors achieve the coupling reactions and these donors can form in situ in the above cases. We show that an electron transfer route can operate either with phenanthrolines as additives or using pyridine as solvent, and we propose new heterocyclic structures for the respective electron donors involved in these cases. In the absence of additives, the coupling reactions are still successful, although more sluggish, and in those cases benzynes are proposed to play crucial roles in the initiation process.
Co-reporter:Florimond Cumine, Shengze Zhou, Tell Tuttle and John A. Murphy
Organic & Biomolecular Chemistry 2017 - vol. 15(Issue 15) pp:NaN3336-3336
Publication Date(Web):2017/03/29
DOI:10.1039/C7OB00036G
Several diketopiperazines have been shown to promote carbon–carbon coupling between benzene and aryl halides in the presence of potassium tert-butoxide and without the assistance of a transition metal catalyst. The structure of the diketopiperazine has an influence on its reductive potential and can help to promote the coupling of the more challenging aryl bromides with benzene.
Co-reporter:Eswararao Doni and John A. Murphy
Inorganic Chemistry Frontiers 2014 - vol. 1(Issue 9) pp:
Publication Date(Web):
DOI:10.1039/C4QO00202D
Co-reporter:Katie J. Emery, John A. Murphy and Tell Tuttle
Organic & Biomolecular Chemistry 2017 - vol. 15(Issue 4) pp:NaN927-927
Publication Date(Web):2016/12/23
DOI:10.1039/C6OB02684B
A recent paper identified a series of alternative cyclisation pathways of aryl radicals that resulted from electron transfer to various tethered haloarene–acetylarene substrates, in either benzene or DMSO as solvent. The electron transfer occurred from one of two enolates that were formed in the presence of KOtBu: either the enolate of the acetylarene, within the haloarene–acetylarene substrate, or the enolate 7 of the N,N′-dipropyl diketopiperazine (DKP) additive 6. This paper uses contemporary computational methods to determine the reaction pathways involved; depending on the substrate, the aryl radical underwent (i) SRN1 onto the enolate anion of the acetylarene, (ii) aryl–aryl bond formation, (iii) tandem hydrogen atom abstraction followed by SRN1 cyclisation and even (iv) ArC–N cleavage. The influence of the solvent was investigated. In this paper it is shown that the solvent influences which reactive species are present in the reaction mixture, and whether each species acts as an electron donor or an electron acceptor in the radical initiation or propagation steps. The main initiation step is a single electron transfer from the enolate anion 7 of the DKP additive in benzene, but in DMSO the initiation can occur from the enolate anion of the substrate itself. Using computational techniques a deeper understanding of the radical pathways involved has been obtained, which shows how we can use solvent to preferentially access products arising from either SRN1 or aryl–aryl bond formation pathways.
Co-reporter:Ryan Sword, Luke A. Baldwin and John A. Murphy
Organic & Biomolecular Chemistry 2011 - vol. 9(Issue 9) pp:NaN3570-3570
Publication Date(Web):2011/02/22
DOI:10.1039/C0OB01282C
Reactions of super-electron-donors (SEDs) derived from 4-dimethylaminopyridine and from N-methylbenzimidazole with α-methoxy-γ-alkoxyalkyl iodides lead to liberation of the γ-alkoxy groups as their alcohols. This is consistent with generation of alkyl radicals from the alkyl halide precursors, and trapping of these radicals by the radical-cation of the SED, followed by a heterolytic fragmentation.
Co-reporter:Hardeep S. Farwaha, Götz Bucher and John A. Murphy
Organic & Biomolecular Chemistry 2013 - vol. 11(Issue 46) pp:NaN8081-8081
Publication Date(Web):2013/10/11
DOI:10.1039/C3OB41701H
Tricyclic donor 26 has been prepared and is the most reducing neutral ground-state organic molecule known, with an oxidation potential 260 mV more negative than the previous record. Cyclic voltammetry shows that a 2-electron reversible redox process occurs in DMF as solvent at −1.46 V vs. Ag/AgCl.
Co-reporter:Eswararao Doni and John A. Murphy
Chemical Communications 2014 - vol. 50(Issue 46) pp:NaN6087-6087
Publication Date(Web):2014/03/25
DOI:10.1039/C3CC48969H
In recent times, metal-free chemistry has received significant attention due to its inherent qualities and its potential savings in the costs of (i) reagents and (ii) environmental treatments of residues. In this context, recently developed neutral organic electron-donors have shown an ability to perform challenging reductions that are traditionally the preserve of reactive metals and metal-based complexes, under mild reaction conditions. Hence, this feature article is aimed at describing the evolution of neutral organic super-electron-donors and their rapidly developing applications in electron-transfer reactions.
Co-reporter:Michael J. Corr and John A. Murphy
Chemical Society Reviews 2011 - vol. 40(Issue 5) pp:NaN2292-2292
Publication Date(Web):2011/03/01
DOI:10.1039/C0CS00150C
Hydrogenases catalyse redox reactions with molecular hydrogen, either as substrate or product. The enzymes harness hydrogen as a reductant using metals that are abundant and economical, namely, nickel and iron, and should provide new pointers for the economic use of hydrogen in manmade devices. The most recently discovered and perhaps the most enigmatic of the hydrogenases is the [Fe]-hydrogenase, used by certain microorganisms in the pathway that reduces carbon dioxide to methane. Since its discovery some twenty years ago, [Fe]-hydrogenase has consistently provided structural and mechanistic surprises, often requiring complete re-evaluation of its mechanism of action. This tutorial review combines recent advances in X-ray crystallography and other analytical techniques, as well as in computational studies and in chemical synthesis to provide a platform for understanding this remarkable enzyme type.
Co-reporter:Phillip I. Jolly, Shengze Zhou, Douglas W. Thomson, Jean Garnier, John A. Parkinson, Tell Tuttle and John A. Murphy
Chemical Science (2010-Present) 2012 - vol. 3(Issue 5) pp:NaN1679-1679
Publication Date(Web):2012/02/14
DOI:10.1039/C2SC20054F
Previous efforts to prepare tetraazafulvalenes derived from imidazolium salt precursors have met with little success (one anomalously favourable example is known), and this is in line with the predicted reactivity of these compounds. However, we now report the preparation of a series of these tetraazafulvalenes formed either by deprotonation of 1,3-dialkylimidazolium salts or by Birch reduction of biimidazolium salts. The tetraazafulvalenes are highly reactive; for example, they act as Super-Electron-Donors towards iodoarenes. The two most reactive examples are formed more efficiently by Birch reduction than by the deprotonation route. Nevertheless, even in cases where the deprotonation approach affords a low stationary concentration, the mixture of precursor salt and base still produces the same powerful reductive chemistry that is the hallmark of tetraazafulvalene electron donors.
![Benzene, 1,1'-[(1-methyl-3-phenylpropylidene)bis(sulfonyl)]bis-](http://img.cochemist.com/ccimg/95300/95274-98-9.png)
![Benzene, 1,1'-[(1-methyl-3-phenylpropylidene)bis(sulfonyl)]bis-](http://img.cochemist.com/ccimg/95300/95274-98-9_b.png)
![Spiro[4.5]dec-6-ene](http://img.cochemist.com/ccimg/700/697-28-9.png)
![Spiro[4.5]dec-6-ene](http://img.cochemist.com/ccimg/700/697-28-9_b.png)
![Spiro[3H-indole-3,3'-pyrrolidin]-2(1H)-one, 5-methoxy-1-(phenylmethyl)-](http://img.cochemist.com/ccimg/404900/404871-51-8.png)
![Spiro[3H-indole-3,3'-pyrrolidin]-2(1H)-one, 5-methoxy-1-(phenylmethyl)-](http://img.cochemist.com/ccimg/404900/404871-51-8_b.png)
![1H-Pyrido[3,4-b]indole, 2,3,4,9-tetrahydro-1-(3-methoxyphenyl)-](http://img.cochemist.com/ccimg/6700/6649-95-2.png)
![1H-Pyrido[3,4-b]indole, 2,3,4,9-tetrahydro-1-(3-methoxyphenyl)-](http://img.cochemist.com/ccimg/6700/6649-95-2_b.png)
![CYCLOPENT[B]INDOLE, 1,2,3,4-TETRAHYDRO-4-(METHYLSULFONYL)-](http://img.cochemist.com/ccimg/198100/198014-37-8.png)
![CYCLOPENT[B]INDOLE, 1,2,3,4-TETRAHYDRO-4-(METHYLSULFONYL)-](http://img.cochemist.com/ccimg/198100/198014-37-8_b.png)
![Piperidine, 1-[(4-methylphenyl)sulfonyl]-4-phenyl-](http://img.cochemist.com/ccimg/143700/143632-57-9.png)
![Piperidine, 1-[(4-methylphenyl)sulfonyl]-4-phenyl-](http://img.cochemist.com/ccimg/143700/143632-57-9_b.png)
![BENZENE, [[(TRIFLUOROMETHYL)SULFONYL]METHYL]-](http://img.cochemist.com/ccimg/4900/4855-02-1.png)
![BENZENE, [[(TRIFLUOROMETHYL)SULFONYL]METHYL]-](http://img.cochemist.com/ccimg/4900/4855-02-1_b.png)
![Ethanone, 2-[(methylsulfonyl)oxy]-1,2-diphenyl-](http://img.cochemist.com/ccimg/19300/19255-01-7.png)
![Ethanone, 2-[(methylsulfonyl)oxy]-1,2-diphenyl-](http://img.cochemist.com/ccimg/19300/19255-01-7_b.png)
![BENZENE, [(1E)-3-ETHOXY-1-PROPENYL]-](http://img.cochemist.com/ccimg/5900/5882-84-8.png)
![BENZENE, [(1E)-3-ETHOXY-1-PROPENYL]-](http://img.cochemist.com/ccimg/5900/5882-84-8_b.png)
![[(3-phenylpropyl)sulfonyl]benzene](http://img.cochemist.com/ccimg/17500/17494-61-0.png)
![[(3-phenylpropyl)sulfonyl]benzene](http://img.cochemist.com/ccimg/17500/17494-61-0_b.png)
![Silane, [[(2Z)-4-bromo-2-butenyl]oxy](1,1-dimethylethyl)diphenyl-](http://img.cochemist.com/ccimg/226600/226546-07-2.png)
![Silane, [[(2Z)-4-bromo-2-butenyl]oxy](1,1-dimethylethyl)diphenyl-](http://img.cochemist.com/ccimg/226600/226546-07-2_b.png)
![6H-Dibenzo[b,d]-pyran](http://img.cochemist.com/ccimg/300/229-95-8.png)
![6H-Dibenzo[b,d]-pyran](http://img.cochemist.com/ccimg/300/229-95-8_b.png)
![Benzene, 1-iodo-2-[(3-methyl-2-butenyl)oxy]-](http://img.cochemist.com/ccimg/120600/120568-94-7.png)
![Benzene, 1-iodo-2-[(3-methyl-2-butenyl)oxy]-](http://img.cochemist.com/ccimg/120600/120568-94-7_b.png)
![[1,1'-Biphenyl]-4-amine, N,N-bis([1,1'-biphenyl]-4-yl)-](http://img.cochemist.com/ccimg/6600/6543-20-0.png)
![[1,1'-Biphenyl]-4-amine, N,N-bis([1,1'-biphenyl]-4-yl)-](http://img.cochemist.com/ccimg/6600/6543-20-0_b.png)
![2-Buten-1-ol, 4-[[(1,1-dimethylethyl)diphenylsilyl]oxy]-, (Z)-](http://img.cochemist.com/ccimg/87800/87770-83-0.png)
![2-Buten-1-ol, 4-[[(1,1-dimethylethyl)diphenylsilyl]oxy]-, (Z)-](http://img.cochemist.com/ccimg/87800/87770-83-0_b.png)
![Bicyclo[6.1.0]nonane,9,9-dibromo-](http://img.cochemist.com/ccimg/1200/1196-95-8.png)
![Bicyclo[6.1.0]nonane,9,9-dibromo-](http://img.cochemist.com/ccimg/1200/1196-95-8_b.png)
![N-[2-[formyl(methyl)amino]ethyl]-n-methylformamide](http://img.cochemist.com/ccimg/6700/6632-41-3.png)
![N-[2-[formyl(methyl)amino]ethyl]-n-methylformamide](http://img.cochemist.com/ccimg/6700/6632-41-3_b.png)
![1H-Indole, 2,3-dihydro-2-methyl-1-[(4-methylphenyl)sulfonyl]-](http://img.cochemist.com/ccimg/51400/51315-70-9.png)
![1H-Indole, 2,3-dihydro-2-methyl-1-[(4-methylphenyl)sulfonyl]-](http://img.cochemist.com/ccimg/51400/51315-70-9_b.png)
![Benzene, 1,1'-[cyclopentylidenebis(sulfonyl)]bis-](http://img.cochemist.com/ccimg/88100/88073-51-2.png)
![Benzene, 1,1'-[cyclopentylidenebis(sulfonyl)]bis-](http://img.cochemist.com/ccimg/88100/88073-51-2_b.png)
![8-Azabicyclo[3.2.1]octane,8-methyl-](http://img.cochemist.com/ccimg/600/529-17-9.png)
![8-Azabicyclo[3.2.1]octane,8-methyl-](http://img.cochemist.com/ccimg/600/529-17-9_b.png)
![2-[2-(1,3-dioxoisoindol-2-yl)ethyl]isoindole-1,3-dione](http://img.cochemist.com/ccimg/700/607-26-1.png)
![2-[2-(1,3-dioxoisoindol-2-yl)ethyl]isoindole-1,3-dione](http://img.cochemist.com/ccimg/700/607-26-1_b.png)
![3-NITRO-6,7,8,9-TETRAHYDRO-5H-BENZO[7]ANNULEN-5-ONE](http://img.cochemist.com/ccimg/7600/7507-93-9.png)
![3-NITRO-6,7,8,9-TETRAHYDRO-5H-BENZO[7]ANNULEN-5-ONE](http://img.cochemist.com/ccimg/7600/7507-93-9_b.png)
![Benzene, [(3-methyl-2-butenyl)oxy]-](http://img.cochemist.com/ccimg/14400/14309-15-0.png)
![Benzene, [(3-methyl-2-butenyl)oxy]-](http://img.cochemist.com/ccimg/14400/14309-15-0_b.png)
![1-(2-fluorobenzyl)-1-[3-(1H-imidazol-1-yl)propyl]-3-phenylurea](http://img.cochemist.com/ccimg/6400/6312-12-5.png)
![1-(2-fluorobenzyl)-1-[3-(1H-imidazol-1-yl)propyl]-3-phenylurea](http://img.cochemist.com/ccimg/6400/6312-12-5_b.png)
![Spiro[4.5]decan-6-one](http://img.cochemist.com/ccimg/13400/13388-94-8.png)
![Spiro[4.5]decan-6-one](http://img.cochemist.com/ccimg/13400/13388-94-8_b.png)
![4-[(3-METHOXYPHENYL)METHYLIDENE]-2-METHYL-1,3-OXAZOL-5-ONE](http://img.cochemist.com/ccimg/41900/41888-64-6.png)
![4-[(3-METHOXYPHENYL)METHYLIDENE]-2-METHYL-1,3-OXAZOL-5-ONE](http://img.cochemist.com/ccimg/41900/41888-64-6_b.png)
![N-[2-(1H-indol-3-yl)ethyl]-Benzamide](http://img.cochemist.com/ccimg/4800/4753-09-7.png)
![N-[2-(1H-indol-3-yl)ethyl]-Benzamide](http://img.cochemist.com/ccimg/4800/4753-09-7_b.png)
![2,3-Dihydro-1H-benzo[d]imidazole](http://img.cochemist.com/ccimg/4800/4746-67-2.png)
![2,3-Dihydro-1H-benzo[d]imidazole](http://img.cochemist.com/ccimg/4800/4746-67-2_b.png)
![Spiro[3H-indole-3,3'-pyrrolidin]-2(1H)-one, 5-methoxy-1'-methyl-](http://img.cochemist.com/ccimg/136400/136316-07-9.png)
![Spiro[3H-indole-3,3'-pyrrolidin]-2(1H)-one, 5-methoxy-1'-methyl-](http://img.cochemist.com/ccimg/136400/136316-07-9_b.png)
![4,9-dihydro-1-phenyl-3H-Pyrido[3,4-b]indole](http://img.cochemist.com/ccimg/10100/10022-79-4.png)
![4,9-dihydro-1-phenyl-3H-Pyrido[3,4-b]indole](http://img.cochemist.com/ccimg/10100/10022-79-4_b.png)
![2-[2-(2,4-dinitrophenyl)hydrazinylidene]cyclohexanol](http://img.cochemist.com/ccimg/24900/24847-86-7.png)
![2-[2-(2,4-dinitrophenyl)hydrazinylidene]cyclohexanol](http://img.cochemist.com/ccimg/24900/24847-86-7_b.png)
![2-[(4-methylphenyl)sulfonyl]-1,2,3,4-tetrahydroisoquinoline](http://img.cochemist.com/ccimg/20400/20335-69-7.png)
![2-[(4-methylphenyl)sulfonyl]-1,2,3,4-tetrahydroisoquinoline](http://img.cochemist.com/ccimg/20400/20335-69-7_b.png)
![1-[2-(4-chlorophenyl)ethyl]-6,7-dimethoxy-2-methyl-3,4-dihydro-1h-isoquinoline](http://img.cochemist.com/ccimg/2200/2154-02-1.png)
![1-[2-(4-chlorophenyl)ethyl]-6,7-dimethoxy-2-methyl-3,4-dihydro-1h-isoquinoline](http://img.cochemist.com/ccimg/2200/2154-02-1_b.png)
![1a,2,3,7b-tetrahydronaphtho[1,2-b]oxirene](http://img.cochemist.com/ccimg/2500/2461-34-9.png)
![1a,2,3,7b-tetrahydronaphtho[1,2-b]oxirene](http://img.cochemist.com/ccimg/2500/2461-34-9_b.png)