Co-reporter:Xingguang Li, Zhixun Wang, Xu Ma, Pei-nian Liu, and Liming Zhang
Organic Letters November 3, 2017 Volume 19(Issue 21) pp:5744-5744
Publication Date(Web):October 16, 2017
DOI:10.1021/acs.orglett.7b02624
By using designed biphenyl-2-ylphosphines functionalized with a remote basic groups as ligands, N-alkynyl-o-nosylamides are directly converted to (1E,3E)-1-amido-1,3-dienes with excellent diastereoselectivities under gold catalysis. With allenamides as substrates, the gold-catalyzed isomerizations are high yielding and applicable to a broad substrate scope including various nitrogen protecting groups and exhibit unprecedented (3E)-selectivities for the distal C–C double bond and good regioselectivities. Combining this gold catalysis with one-pot Diels–Alder reactions leads to rapid assembly of valuable bicyclic compounds.
Co-reporter:Zhixun Wang, Corrado Nicolini, Cedric Hervieu, Yuk-Fai Wong, Giuseppe Zanoni, and Liming Zhang
Journal of the American Chemical Society November 15, 2017 Volume 139(Issue 45) pp:16064-16064
Publication Date(Web):October 23, 2017
DOI:10.1021/jacs.7b09136
An accelerative asymmetric gold catalysis is achieved for the first time via chiral ligand metal cooperation. An asymmetrically positioned remote amide group in the designed chiral binaphthyl-based ligand plays the essential role of a general base catalyst and selectively accelerates the cyclizations of 4-allen-1-ols into one prochiral allene face. The reactions are mostly highly enantioselective with achiral substrates, and due to the accelerated nature of the catalysis catalyst loadings as low as 100 ppm are allowed. With a pre-existing chiral center at any of the backbone sp3-carbons, the reaction remained highly efficient and most importantly maintained excellent allene facial selectivities regardless of the substrate stereochemistry. By using different combinations of ligand and substrate enantiomers, it is now possible to access all four stereoisomers of versatile 2-vinyltetrahydrofurans with exceedingly high selectivity. The underpinning design of this chemistry reveals a novel and conceptually distinctive strategy to tackle challenging asymmetric gold catalysis, which to date has relied on decelerative asymmetric steric hindrance approaches.
Co-reporter:Xiaoqing Li, Shengrong Liao, Zhixun Wang, and Liming Zhang
Organic Letters July 21, 2017 Volume 19(Issue 14) pp:3687-3687
Publication Date(Web):July 11, 2017
DOI:10.1021/acs.orglett.7b01359
The direct addition of in situ generated hydrazoic acid to alkynes is realized without solvent by using a gold catalyst derived from a recently designed remotely functionalized biaryl-2-ylphosphine ligand (i.e., WangPhos). With terminal alkynes, the additions are mostly realized with 0.1 mol% catalyst loadings and at 40 °C. With more challenging internal alkynes devoid of direct EWG substitution, the one-step transformation is realized for the first time with generally high efficiency at ambient temperature.
Co-reporter:Zhitong Zheng, Zhixun Wang, Youliang Wang and Liming Zhang
Chemical Society Reviews 2016 vol. 45(Issue 16) pp:4448-4458
Publication Date(Web):19 Jan 2016
DOI:10.1039/C5CS00887E
The two main strategies of gold-catalysed oxidative cyclisation are discussed in this tutorial. The first one employs nucleophilic oxidants as either internal or external nucleophiles. The inherently weak O-heteroatom bond in the oxidant enables the versatile reactivities of the initial gold-promoted adduct of the oxidant to alkyne, including its fragmentation into a highly reactive α-oxo gold carbene intermediate. The second features external oxidant-powered Au(I)/Au(III) catalysis, where the metal oxidation state changes during the catalytic cycle. These strategies have been applied toward the development of a variety of valuable synthetic transformations.
Co-reporter:Wen-Ting Wu, Liming Zhang and Shu-Li You
Chemical Society Reviews 2016 vol. 45(Issue 6) pp:1570-1580
Publication Date(Web):22 Jan 2016
DOI:10.1039/C5CS00356C
Phenols are widely used as starting materials in both industrial and academic society. Dearomatization reactions of phenols provide an efficient way to construct highly functionalized cyclohexadienones. The main challenge to make them asymmetric by catalytic methods is to control the selectivity while overcoming the loss of aromaticity. In this tutorial review, an up to date summary of recent progress in CADA reactions of phenol and aniline derivatives is presented.
Co-reporter:Zhou Xu; Hongyi Chen; Zhixun Wang; Anguo Ying
Journal of the American Chemical Society 2016 Volume 138(Issue 17) pp:5515-5518
Publication Date(Web):April 15, 2016
DOI:10.1021/jacs.6b02533
Enolate umpolung reactivities offer valuable and potentially unique alternatives over the enolate counterparts for the construction of ubiquitous carbonyl compounds. We disclose here that N-alkenoxypyridinium salts, generated readily upon gold-catalyzed additions of protonated pyridine N-oxide to C–C triple bonds of unactivated terminal alkynes, display versatile enolate umpolung chemistry upon heating and react with tethered arene nucleophiles in an SN2′ manner. In a synthetically efficient one-pot, two-step process, this chemistry enables expedient preparation of valuable benzo-fused seven-/eight-membered cyclic ketones, including those of O-/N-heterocycles, from easily accessible aryl-substituted linear alkyne substrates. The reaction yields can be up to 87%.
Co-reporter:Youliang Wang; Maxence Zarca; Liu-Zhu Gong
Journal of the American Chemical Society 2016 Volume 138(Issue 24) pp:7516-7519
Publication Date(Web):June 8, 2016
DOI:10.1021/jacs.6b04297
Cyclopentenones are synthetically versatile structures, and their straightforward construction from alkynone substrates by employing synthetically streamlining C–H insertion is conceptually appealing and of high synthetic potential. But, its implementation is very limited. Herein we report a Au-catalyzed version, which affords 2-bromocyclopent-2-en-1-ones with a broad scope and synthetically desirable diastereoselectivities. The proposed key intermediate capable of the observed insertion into unactivated C–H bonds is a fully functionalized gold vinylidene, which is generated via a novel intermolecular strategy. This flexible access of likely gold vinylidenes opens various opportunities to explore their versatile reactivities.
Co-reporter:Wen-Ting Wu, Ren-Qi Xu, Liming Zhang and Shu-Li You
Chemical Science 2016 vol. 7(Issue 5) pp:3427-3431
Publication Date(Web):02 Feb 2016
DOI:10.1039/C5SC04130A
A highly efficient, gold-catalyzed intramolecular dearomatization reaction of naphthols via 5-endo-dig cyclization is described. This facile and direct approach furnishes spirocarbocycles in excellent yields under mild conditions.
Co-reporter:Youliang Wang; Zhitong Zheng
Journal of the American Chemical Society 2015 Volume 137(Issue 16) pp:5316-5319
Publication Date(Web):April 2, 2015
DOI:10.1021/jacs.5b02280
Generation of reactive α-oxo gold carbene intermediates via gold-catalyzed oxidation of alkynes has become an increasing versatile strategy of replacing hazardous diazo carbonyl compounds with benign and readily available alkynes in the development of efficient synthetic methods. However, one of the hallmarks of metal carbene/carbenoid chemistry, i.e., insertion into an unactivated C(sp3)–H bond, has not be realized. This study reveals for the first time that this highly valuable transformation can be readily realized intramolecularly by oxidatively generated β-diketone-α-gold carbenes using ynones as substrates. Substrate conformation control via the Thorpe–Ingold effect is the key design feature that enables generally good to excellent efficiencies, and synthetically versatile cyclopentanones including spiro-, bridged, and fused bicyclic ones can be readily accessed.
Co-reporter:Renhua Zheng, Youliang Wang, Liming Zhang
Tetrahedron Letters 2015 Volume 56(Issue 23) pp:3144-3146
Publication Date(Web):3 June 2015
DOI:10.1016/j.tetlet.2014.11.138
Our previously developed strategy of generating ketene intermediates via Ru-catalyzed intramolecular oxidation of terminal alkynes is applied to propargyl sulfoxides. The reaction undergoes interesting further rearrangement upon the ketene generation to afford α,β-unsaturated thioesters in good to excellent yields in the reported cases.
Co-reporter:Hongyi Chen ;Dr. Liming Zhang
Angewandte Chemie 2015 Volume 127( Issue 40) pp:11941-11945
Publication Date(Web):
DOI:10.1002/ange.201504511
Abstract
Donor-substituted acyl gold carbenes are challenging to access selectively by gold-promoted intermolecular oxidation of internal alkynes as the opposite regioisomers frequently predominate. By using alkynyl sulfones or sulfonates as substrates, the oxidative gold catalysis in the presence of substituted pyridine N-oxides offers regiospecific access to acyl/aryl, acyl/alkenyl, and acyl/alkoxy gold carbenes by in situ expulsion of sulfur dioxide. The intermediacies of these reactive species are established by their reactivities, including undergoing further oxidation by the same oxidant, cyclopropanation of styrenes, engaging in a [3+2] cycloaddition with α-methylstyrene, and conversion into dienones.
Co-reporter:Hongyi Chen ;Dr. Liming Zhang
Angewandte Chemie International Edition 2015 Volume 54( Issue 40) pp:11775-11779
Publication Date(Web):
DOI:10.1002/anie.201504511
Abstract
Donor-substituted acyl gold carbenes are challenging to access selectively by gold-promoted intermolecular oxidation of internal alkynes as the opposite regioisomers frequently predominate. By using alkynyl sulfones or sulfonates as substrates, the oxidative gold catalysis in the presence of substituted pyridine N-oxides offers regiospecific access to acyl/aryl, acyl/alkenyl, and acyl/alkoxy gold carbenes by in situ expulsion of sulfur dioxide. The intermediacies of these reactive species are established by their reactivities, including undergoing further oxidation by the same oxidant, cyclopropanation of styrenes, engaging in a [3+2] cycloaddition with α-methylstyrene, and conversion into dienones.
Co-reporter:Dr. Kegong Ji;Zhitong Zheng;Zhixun Wang;Dr. Liming Zhang
Angewandte Chemie 2015 Volume 127( Issue 4) pp:1261-1265
Publication Date(Web):
DOI:10.1002/ange.201409300
Abstract
A newly developed P,N-bidentate ligand enables enantioselective intramolecular cyclopropanation by a reactive α-oxo gold carbene intermediate generated in situ. The ligand design is based on our previously proposed structure (with a well-organized triscoordinated gold center) of the carbene intermediate in the presence of a P,N-bidentate ligand. A C2-symmetric piperidine ring was incorporated in the ligand as the nitrogen-containing moiety. A range of racemic transformations of α-oxo gold carbene intermediates have been developed recently, and this new class of chiral ligands could enable their modification for asymmetric synthesis, as demonstrated in this study.
Co-reporter:Dr. Kegong Ji;Zhitong Zheng;Zhixun Wang;Dr. Liming Zhang
Angewandte Chemie International Edition 2015 Volume 54( Issue 4) pp:1245-1249
Publication Date(Web):
DOI:10.1002/anie.201409300
Abstract
A newly developed P,N-bidentate ligand enables enantioselective intramolecular cyclopropanation by a reactive α-oxo gold carbene intermediate generated in situ. The ligand design is based on our previously proposed structure (with a well-organized triscoordinated gold center) of the carbene intermediate in the presence of a P,N-bidentate ligand. A C2-symmetric piperidine ring was incorporated in the ligand as the nitrogen-containing moiety. A range of racemic transformations of α-oxo gold carbene intermediates have been developed recently, and this new class of chiral ligands could enable their modification for asymmetric synthesis, as demonstrated in this study.
Co-reporter:Zhixun Wang ; Yanzhao Wang
Journal of the American Chemical Society 2014 Volume 136(Issue 25) pp:8887-8890
Publication Date(Web):June 9, 2014
DOI:10.1021/ja503909c
By functionalizing the privileged biphenyl-2-ylphosphine with a basic amino group at the rarely explored 3′ position, the derived gold(I) complex possesses orthogonally positioned “push” and “pull” forces, which enable for the first time soft propargylic deprotonation and permit the bridging of a difference of >26 pKa units (in DMSO) between a propargylic hydrogen and a protonated tertiary aniline. The application of this design led to efficient isomerization of alkynes into versatile 1,3-dienes with synthetically useful scope under mild reaction conditions.
Co-reporter:Jiabin Li, Kegong Ji, Renhua Zheng, Jonathan Nelson and Liming Zhang
Chemical Communications 2014 vol. 50(Issue 31) pp:4130-4133
Publication Date(Web):13 Mar 2014
DOI:10.1039/C4CC00739E
With a new P,S-bidentate phosphine as the ligand to gold(I), the α-oxo gold carbenes generated in situ via gold-catalyzed intermolecular oxidation of terminal alkynes were effectively trapped by various allylic sulfides, resulting in the formation of α-aryl(alkyl)thio-γ,δ-unsaturated ketones upon facile [2,3]sigmatropic rearrangements.
Co-reporter:Gongde Wu;Renhua Zheng;Jonathan Nelson
Advanced Synthesis & Catalysis 2014 Volume 356( Issue 6) pp:1229-1234
Publication Date(Web):
DOI:10.1002/adsc.201300855
Co-reporter:Zhitong Zheng;Huangfei Tu ; Dr. Liming Zhang
Chemistry - A European Journal 2014 Volume 20( Issue 9) pp:2445-2448
Publication Date(Web):
DOI:10.1002/chem.201304204
Abstract
A two-step, one-pot synthesis of fused pyrroles is realized by firstly condensing an N-alkynylhydroxammonium salt with a readily enolizable ketone under mild basic conditions and then subjecting the reaction mixture to a gold catalyst, which triggers a cascade reaction involving a facile initial [3.3]-sigmatropic rearrangement of the gold-catalysis product, that is, an N,O-dialkenylhydroxamine. The reaction provides a facile access to polycyclic pyrroles in moderate to good yields.
Co-reporter:Youliang Wang;Zhitong Zheng ;Dr. Liming Zhang
Angewandte Chemie International Edition 2014 Volume 53( Issue 36) pp:9572-9576
Publication Date(Web):
DOI:10.1002/anie.201403796
Abstract
The oxidation of in situ generated Ru vinylidenes to ketenes is realized with tethered sulfoxides. The result is a Ru-catalyzed oxidative transformation of terminal alkynes to highly valuable ketenes. Moreover, the ketenes generated here were shown to undergo characteristic ketene [2+2] cycloaddition reactions with tethered alkenes and external imines, yielding synthetically versatile bicyclic cyclobutanones and β-lactams, respectively.
Co-reporter:Youliang Wang;Zhitong Zheng ;Dr. Liming Zhang
Angewandte Chemie 2014 Volume 126( Issue 36) pp:9726-9730
Publication Date(Web):
DOI:10.1002/ange.201403796
Abstract
The oxidation of in situ generated Ru vinylidenes to ketenes is realized with tethered sulfoxides. The result is a Ru-catalyzed oxidative transformation of terminal alkynes to highly valuable ketenes. Moreover, the ketenes generated here were shown to undergo characteristic ketene [2+2] cycloaddition reactions with tethered alkenes and external imines, yielding synthetically versatile bicyclic cyclobutanones and β-lactams, respectively.
Co-reporter:Kegong Ji, Brendan D'Souza, Jon Nelson, Liming Zhang
Journal of Organometallic Chemistry 2014 770() pp: 142-145
Publication Date(Web):
DOI:10.1016/j.jorganchem.2014.08.005
Co-reporter:Zhitong Zheng;Mollie Touve;Josue Barnes;Dr. Norbert Reich;Dr. Liming Zhang
Angewandte Chemie International Edition 2014 Volume 53( Issue 35) pp:9302-9305
Publication Date(Web):
DOI:10.1002/anie.201402268
Abstract
A DNA crosslinking approach, which is distinct but related to the double alkylation by mitomycin C, involving a novel electrophilic spiro-cyclopropane intermediate is hypothesized. Rational design and substantial structural simplification permitted the expedient chemical synthesis and rapid discovery of MTSB-6, a mitomycin C analogue which is twice as potent as mitomycin C against the prostate cancer cells. MTSB-6 shows improvements in its selective action against noncancer prostate cells over mitomycin C. This hypothesis-driven discovery opens novel yet synthetically accessible mitosene structural space for discovering more potent and less toxic therapeutic candidates.
Co-reporter:Biao Lu ; Yuxue Li ; Youliang Wang ; Donald H. Aue ; Yingdong Luo
Journal of the American Chemical Society 2013 Volume 135(Issue 23) pp:8512-8524
Publication Date(Web):June 3, 2013
DOI:10.1021/ja401343p
Gold-catalyzed intramolecular oxidation of terminal alkynes with an arenesulfinyl group as the tethered oxidant is a reaction of high impact in gold chemistry, as it introduced to the field the highly valued concept of gold carbene generation via alkyne oxidation. The proposed intermediacy of α-oxo gold carbenes in these reactions, however, has never been substantiated. Detailed experimental studies suggest that the involvement of such reactive intermediates in the formation of dihydrobenzothiepinones is highly unlikely. Instead, a [3,3]-sigmatropic rearrangement of the initial cyclization intermediate offers a reaction path that can readily explain the high reaction efficiency and the lack of sulfonium formation. With internal alkyne substrates, however, the generation of a gold carbene species becomes competitive with the [3,3]-sigmatropic rearrangement. This reactive intermediate, nevertheless, does not proceed to afford the Friedel–Crafts-type cyclization product. Extensive density functional theory studies support the mechanistic conclusion that the cyclized product is formed via an intramolecular [3,3]-sigmatropic rearrangement instead of the previously proposed Friedel–Crafts-type cyclization. With the new mechanistic insight, the product scope of this versatile formation of mid-sized sulfur-containing cycloalkenones has been expanded readily to various dihydrobenzothiocinones, a tetrahydrobenzocyclononenone, and even those without the entanglement of a fused benzene ring. Besides gold, Hg(OTf)2 can be an effective catalyst, thereby offering a cheap alternative for this intramolecular redox reaction.
Co-reporter:Yanzhao Wang, Lianzhu Liu and Liming Zhang
Chemical Science 2013 vol. 4(Issue 2) pp:739-746
Publication Date(Web):05 Dec 2012
DOI:10.1039/C2SC21333H
The Fischer indole synthesis is perhaps the most powerful method for indole preparation, but it often suffers from low regioselectivities with unsymmetrical aliphatic ketone substrates and strongly acidic conditions and is not suitable for α,β-unsaturated ketones. In this edge article, we disclose an efficient synthesis of N-protected indoles from N-arylhydroxamic acids/N-aryl-N-hydroxycarbamates and a variety of alkynes via cooperative gold and zinc catalysis. The zinc catalysis is similar to the related zinc ion catalysis in metalloenzymes such as human carbonic anhydrase II and substantially enhances the O-nucleophilicity of N-acylated hydroxylamine by forming the corresponding Zn chelates. The Zn chelates can attack gold-activated alkynes to form O-alkenyl-N-arylhydroxamates, which can undergo facile 3,3-sigmatropic rearrangements and subsequent cyclodehydrations to yield N-protected indole products. This new chemistry offers several important improvements over the Fischer indole synthesis: (a) the reaction conditions are mildly acidic and can tolerate sensitive groups such as Boc; (b) broader substrate scopes including substrates with pendant carbonyl groups (reactive in the Fischer chemistry) and alkyl chlorides; (c) better regioselectivities for the formation of 2-substituted indoles under much milder conditions; (d) 2-alkenylindoles can be prepared readily in good to excellent yields, for which Fischer chemistry could not be used; (e) with internal alkynes both steric and electronic controls are available for achieving good regioselectivities, while Fischer chemistry is in general problematic.
Co-reporter:Dr. Kegong Ji;Dr. Yulong Zhao ;Dr. Liming Zhang
Angewandte Chemie 2013 Volume 125( Issue 25) pp:6636-6640
Publication Date(Web):
DOI:10.1002/ange.201301601
Co-reporter:Dr. Kegong Ji;Dr. Yulong Zhao ;Dr. Liming Zhang
Angewandte Chemie International Edition 2013 Volume 52( Issue 25) pp:6508-6512
Publication Date(Web):
DOI:10.1002/anie.201301601
Co-reporter:Youliang Wang;Akop Yepremyan;Dr. Subir Ghorai;Dr. Robert Todd;Dr. Donald H. Aue;Dr. Liming Zhang
Angewandte Chemie International Edition 2013 Volume 52( Issue 30) pp:7795-7799
Publication Date(Web):
DOI:10.1002/anie.201301057
Co-reporter:Yingdong Luo ; Kegong Ji ; Yuxue Li
Journal of the American Chemical Society 2012 Volume 134(Issue 42) pp:17412-17415
Publication Date(Web):October 5, 2012
DOI:10.1021/ja307948m
2,4-Oxazole is an important structural motif in various natural products. An efficient modular synthesis of this structure has been achieved via a [3 + 2] annulation between a terminal alkyne and a carboxamide using a gold-catalyzed oxidation strategy. The postulated reactive intermediate, a terminal α-oxo gold carbene, previously known to be highly electrophilic and hence unlikely to be trapped by stoichiometric external nucleophiles, is coerced to react smoothly with the carboxamide en route to the oxazole ring by a P,N- or P,S-bidentate ligand such as Mor-DalPhos; in stark contrast, often-used ligands such as monodentate phosphines and N-heterocyclic carbenes are totally ineffective. The role of these bidentate phosphines in this reaction is attributed to the formation of a tricoordinated gold carbene intermediate, which is less electrophilic and hence more chemoselective when reacting with nucleophiles. The success in using bidentate phosphine ligands to temper the reactivities of in situ-generated gold carbenes is likely to open many new opportunities to apply oxidative gold catalysis to the development of novel methods, and the implication of tricoordinated gold intermediates in homogeneous gold catalysis should stimulate further advances in gold catalysis.
Co-reporter:Yuanjing Xiao and Liming Zhang
Organic Letters 2012 Volume 14(Issue 17) pp:4662-4665
Publication Date(Web):August 23, 2012
DOI:10.1021/ol302102h
The cyclic α-imino gold carbene intermediate B is most likely generated in situ via regioselective nitrene transfer from an azido group to a tethered terminal alkyne in the presence of a gold catalyst and at ambient temperature. This highly electrophilic intermediate can react with a weakly nucleophilic nitrile, which is used as the reaction solvent, to deliver a bicyclic imidazole rapidly in an overall bimolecular [2 + 2 + 1] cycloaddition and in mostly serviceable yield. The competing intramolecular Huisgen reaction, although likely also catalyzed by gold, is minimized by using AuCl3 as the catalyst.
Co-reporter:Lianzhu Liu, Yanzhao Wang, and Liming Zhang
Organic Letters 2012 Volume 14(Issue 14) pp:3736-3739
Publication Date(Web):July 5, 2012
DOI:10.1021/ol301593w
A formal synthesis of 7-methoxymitosene is achieved via a key platinum-catalyzed cycloisomerization. The precursor for the Pt catalysis, a fully functionalized benzene intermediate, was prepared via a regioselective electrophilic bromination followed by a chemoselective Sonogashira cross-coupling. It underwent the PtCl2-catalyzed cycloisomerization smoothly despite its hindered and highly electron-rich nature. Analogs of 7-methoxymitosene can be accessed in an expedient manner by following a similar synthetic sequence.
Co-reporter:Weimin He, Longyong Xie, Yingying Xu, Jiannan Xiang and Liming Zhang
Organic & Biomolecular Chemistry 2012 vol. 10(Issue 16) pp:3168-3171
Publication Date(Web):14 Mar 2012
DOI:10.1039/C2OB25235J
α-Oxo gold carbenes generated via intermolecular oxidation of terminal alkynes are shown to be highly electrophilic and can effectively abstract halogen from halogenated solvents such as 1,2-dichloroethane or 1,2-dibromoethane. Chloro/bromomethyl ketones are prepared in moderate efficiencies in one step using Ph3PAuNTf2 as the catalyst and 8-methylquinoline N-oxide as the oxidant.
Co-reporter:Yanzhao Wang;Dr. Kegong Ji;Sylvester Lan ;Dr. Liming Zhang
Angewandte Chemie 2012 Volume 124( Issue 8) pp:1951-1954
Publication Date(Web):
DOI:10.1002/ange.201107561
Co-reporter:Dr. Ze-Yi Yan;Dr. Yuanjing Xiao ;Dr. Liming Zhang
Angewandte Chemie 2012 Volume 124( Issue 34) pp:8752-8755
Publication Date(Web):
DOI:10.1002/ange.201203678
Co-reporter:Dr. Lianzhu Liu ;Dr. Liming Zhang
Angewandte Chemie 2012 Volume 124( Issue 29) pp:7413-7416
Publication Date(Web):
DOI:10.1002/ange.201203303
Co-reporter:Dr. Ze-Yi Yan;Dr. Yuanjing Xiao ;Dr. Liming Zhang
Angewandte Chemie International Edition 2012 Volume 51( Issue 34) pp:8624-8627
Publication Date(Web):
DOI:10.1002/anie.201203678
Co-reporter:Dr. Lianzhu Liu ;Dr. Liming Zhang
Angewandte Chemie International Edition 2012 Volume 51( Issue 29) pp:7301-7304
Publication Date(Web):
DOI:10.1002/anie.201203303
Co-reporter:Yanzhao Wang;Dr. Kegong Ji;Sylvester Lan ;Dr. Liming Zhang
Angewandte Chemie International Edition 2012 Volume 51( Issue 8) pp:1915-1918
Publication Date(Web):
DOI:10.1002/anie.201107561
Co-reporter:Weimin He ; Chaoqun Li
Journal of the American Chemical Society 2011 Volume 133(Issue 22) pp:8482-8485
Publication Date(Web):May 12, 2011
DOI:10.1021/ja2029188
The first efficient intermolecular reaction of gold carbene intermediates generated via gold-catalyzed alkyne oxidation has been realized using nitriles as both the reacting partner and the reaction solvent, offering a generally efficient synthesis of 2,5-disubstituted oxazoles with broad substrate scope. The overall reaction is a [2 + 2 + 1] annulation of a terminal alkyne, a nitrile, and an oxygen atom from an oxidant. The reaction conditions are exceptionally mild, and a range of functional groups are easily tolerated. With complex and/or expensive nitriles, only 3 equiv could be sufficient to achieve serviceable yields in the absence of any solvent and using only 1 mol % BrettPhosAuNTf2 as the catalyst.
Co-reporter:Elizabeth L. Noey ; Yingdong Luo ; Liming Zhang ;K. N. Houk
Journal of the American Chemical Society 2011 Volume 134(Issue 2) pp:1078-1084
Publication Date(Web):December 22, 2011
DOI:10.1021/ja208860x
Quantum mechanical studies of the mechanism of gold-catalyzed rearrangements of acetylenic amine-N-oxides to piperidinones or azepanones have revealed a new mechanism involving a concerted heteroretroene reaction, formally a 1,5 hydrogen shift from the N-alkyl groups to the vinyl position of a gold-coordinated methyleneisoxazolidinium or methyleneoxazinanium. Density functional calculations (B3LYP, B3LYP-D3) on the heteroretroene mechanism reproduce experimental regioselectivities and provide an explanation as to why the hydrogen is transferred from the smaller amine substituent. In support of the proposed mechanism, new experimental investigations show that the hydrogen shift is concerted and that gold carbenes are not involved as reaction intermediates.
Co-reporter:Yanzhao Wang, Longwu Ye and Liming Zhang
Chemical Communications 2011 vol. 47(Issue 27) pp:7815-7817
Publication Date(Web):03 Jun 2011
DOI:10.1039/C1CC12212F
The first gold-catalyzed addition of N-arylhydroxylamines to aliphatic terminal alkynes is developed to access O-alkenyl-N-arylhydroxylamines, which undergo facile in situ sequential 3,3-rearrangements and cyclodehydrations to afford 2-alkylindoles with regiospecificity and under exceptionally mild reaction conditions.
Co-reporter:Guozhu Zhang;Yingdong Luo;Yanzhao Wang ;Dr. Liming Zhang
Angewandte Chemie International Edition 2011 Volume 50( Issue 19) pp:4450-4454
Publication Date(Web):
DOI:10.1002/anie.201100293
Co-reporter:Dr. Longwu Ye;Weimin He ;Dr. Liming Zhang
Angewandte Chemie International Edition 2011 Volume 50( Issue 14) pp:3236-3239
Publication Date(Web):
DOI:10.1002/anie.201007624
Co-reporter:Dr. Biao Lu;Yingdong Luo;Dr. Lianzhu Liu;Dr. Longwu Ye;Yanzhao Wang ;Dr. Liming Zhang
Angewandte Chemie 2011 Volume 123( Issue 36) pp:8508-8512
Publication Date(Web):
DOI:10.1002/ange.201103014
Co-reporter:Guozhu Zhang;Yingdong Luo;Yanzhao Wang ;Dr. Liming Zhang
Angewandte Chemie 2011 Volume 123( Issue 19) pp:4542-4546
Publication Date(Web):
DOI:10.1002/ange.201100293
Co-reporter:Dr. Longwu Ye;Weimin He ;Dr. Liming Zhang
Angewandte Chemie 2011 Volume 123( Issue 14) pp:3294-3297
Publication Date(Web):
DOI:10.1002/ange.201007624
Co-reporter:Dr. Biao Lu;Yingdong Luo;Dr. Lianzhu Liu;Dr. Longwu Ye;Yanzhao Wang ;Dr. Liming Zhang
Angewandte Chemie International Edition 2011 Volume 50( Issue 36) pp:8358-8362
Publication Date(Web):
DOI:10.1002/anie.201103014
Co-reporter:Longwu Ye ; Li Cui ; Guozhu Zhang
Journal of the American Chemical Society 2010 Volume 132(Issue 10) pp:3258-3259
Publication Date(Web):February 18, 2010
DOI:10.1021/ja100041e
An expedient and reliable method for accessing reactive α-oxo gold carbenes via gold-catalyzed intermolecular oxidation of terminal alkynes has been developed. Significantly, this method offers a safe and economical alternative to the strategies based on diazo substrates. Its synthetic potential is demonstrated by expedient preparation of dihydrofuran-3-ones containing a broad range of functional groups.
Co-reporter:Guozhu Zhang ; Li Cui ; Yanzhao Wang
Journal of the American Chemical Society 2010 Volume 132(Issue 5) pp:1474-1475
Publication Date(Web):January 5, 2010
DOI:10.1021/ja909555d
Homogeneous carboamination, carboalkoxylation and carbolactonization of terminal alkenes are realized via oxidative gold catalysis, providing expedient access to various substituted N- or O-heterocycles. Deuterium-labeling studies established the anti nature of the alkene functionalization and the indispensible role of Au(I)/Au(III) catalysis. This study constitutes the first example of catalytically converting C(sp3)−Au bonds into C(sp3)−-C(sp2) bonds in a cross-coupling manner and opens new opportunities to study gold alkene catalysis where alkylgold intermediates can be readily functionalized intermolecularly.
Co-reporter:Longwu Ye ; Weimin He
Journal of the American Chemical Society 2010 Volume 132(Issue 25) pp:8550-8551
Publication Date(Web):June 3, 2010
DOI:10.1021/ja1033952
A general solution for the synthesis of various oxetan-3-ones is developed. This reaction uses readily available propargylic alcohols as substrates and proceeds without the exclusion of moisture or air (“open flask”). Notably, oxetan-3-one, a highly valuable substrate for drug discovery, can be prepared in one step from propargyl alcohol in a fairly good yield. The facile formation of the strained oxetane ring provides strong support for the intermediacy of α-oxo gold carbenes. This safe and efficient generation of gold carbenes via intermolecular alkyne oxidation offers a potentially general entry into α-oxo metal carbene chemistry without using hazardous diazo ketones.
Co-reporter:Yanzhao Wang, Biao Lu and Liming Zhang
Chemical Communications 2010 vol. 46(Issue 48) pp:9179-9181
Publication Date(Web):29 Oct 2010
DOI:10.1039/C0CC03669B
A gold-catalyzed synthesis of 1-bromo/chloro-2-carboxy-1,3-dienes is developed using propargylic carboxylates containing halogenated alkynes as substrates. The reaction is highly diastereoselective, and the halogen atom at the alkyne terminus selectively promotes a 1,2-acyloxy migration. The diene products participate in the Diels–Alder and cross-coupling reactions.
Co-reporter:Li Cui, Longwu Ye and Liming Zhang
Chemical Communications 2010 vol. 46(Issue 19) pp:3351-3353
Publication Date(Web):30 Mar 2010
DOI:10.1039/C001314E
A surprisingly efficient synthesis of azepan-4-ones via a two-step [5+2] annulation is developed. This reaction involves a key gold catalysis and shows generally high regioselectivities and good to excellent diastereoselectivities.
Co-reporter:Dr. Li Cui;Dr. Chaoqun Li ;Dr. Liming Zhang
Angewandte Chemie International Edition 2010 Volume 49( Issue 48) pp:9178-9181
Publication Date(Web):
DOI:10.1002/anie.201004712
Co-reporter:Dr. Li Cui;Dr. Chaoqun Li ;Dr. Liming Zhang
Angewandte Chemie 2010 Volume 122( Issue 48) pp:9364-9367
Publication Date(Web):
DOI:10.1002/ange.201004712
Co-reporter:Li Cui
Science China Chemistry 2010 Volume 53( Issue 1) pp:113-118
Publication Date(Web):2010 January
DOI:10.1007/s11426-010-0010-6
Total syntheses of (+)-lentiginosine and its 8a-epimer using a gold-catalyzed oxidative cyclization as the key step were realized. The gold chemistry, reported previously in a [4+2] synthesis of piperidin-4-ones, tolerates functionalized structures and is compatible with several protecting strategies albeit with low diastereoselectivities.
Co-reporter:SanSan Cao
Science China Chemistry 2009 Volume 52( Issue 9) pp:1337-1344
Publication Date(Web):2009 September
DOI:10.1007/s11426-009-0194-9
From readily available propargylic carboxylates, two sequential transformations—gold-catalyzed tandem reactions and Sc(OTf)3-catalyzed cyclization—in a one-pot process led to the formation of 2-acylcyclohexenones with an electron-rich arene ring fused at the 4,5-positions.
Co-reporter:Longwu Ye ; Yanzhao Wang ; Donald H. Aue
Journal of the American Chemical Society () pp:
Publication Date(Web):December 14, 2011
DOI:10.1021/ja2091992
Facile cycloisomerization of (2-ethynylphenyl)alkynes is proposed to be promoted synergistically by two molecules of BrettPhosAuNTf2, affording tricyclic indenes in mostly good yields. A gold vinylidene is most likely generated as one of the reaction intermediates on the basis of both mechanistic studies and theoretical calculations. Different from the well-known Rh, Ru, and W counterparts, this novel gold species is highly reactive and undergoes facile intramolecular C(sp3)–H insertions as well as O–H and N–H insertions. The formation step for the gold vinylidene is predicted theoretically to be complex with a bifurcated reaction pathway. A pyridine N-oxide acts as a weak base to facilitate the formation of an alkynylgold intermediate, and the bulky BrettPhos ligand in the gold catalyst likely plays a role in sterically steering the reaction toward formation of the gold vinylidene.
Co-reporter:Biao Lu ; Chaoqun Li
Journal of the American Chemical Society () pp:
Publication Date(Web):
DOI:10.1021/ja1072614
Gold-catalyzed intermolecular oxidations of internal alkynes have been achieved with high regioselectivities using 8-alkylquinoline N-oxides as oxidants and in the absence of acid additives. Synthetically versatile α,β-unsaturated carbonyls are obtained in good to excellent yields and with excellent E-selectivities. A range of functional groups such as THP, MOMO, N3, OTBS, and N-Boc are tolerated. This reaction allows α,β-unsaturated carbonyls to be masked as propargyl moieties, thus offering a practical solution to compatibility issues with these functional groups likely encountered in syntheses of complex structures.
Co-reporter:Zhitong Zheng and Liming Zhang
Inorganic Chemistry Frontiers 2015 - vol. 2(Issue 12) pp:
Publication Date(Web):
DOI:10.1039/C5QO00308C
Co-reporter:Kegong Ji and Liming Zhang
Inorganic Chemistry Frontiers 2014 - vol. 1(Issue 1) pp:NaN38-38
Publication Date(Web):2014/02/13
DOI:10.1039/C3QO00080J
What a trade: diazo ketones for alkynes? By utilizing a conformationally rigid P,N-bidentate ligand, highly efficient intramolecular cyclopropanation reactions using flexible and electronically neutral terminal alkyne substrates are realized via a sterically shielded tri-coordinated gold carbene intermediate. Bicyclic/tricyclic functionalized cyclopropyl ketones are formed in mostly good yields in three steps from readily available enones/enals, which compares favorably with related strategies based on the diazo approach in terms of step economy and operational safety. With this chemistry, we have expanded alkynes as surrogates of α-diazo ketones to cyclopropanation reactions.
Co-reporter:Jiabin Li, Kegong Ji, Renhua Zheng, Jonathan Nelson and Liming Zhang
Chemical Communications 2014 - vol. 50(Issue 31) pp:NaN4133-4133
Publication Date(Web):2014/03/13
DOI:10.1039/C4CC00739E
With a new P,S-bidentate phosphine as the ligand to gold(I), the α-oxo gold carbenes generated in situ via gold-catalyzed intermolecular oxidation of terminal alkynes were effectively trapped by various allylic sulfides, resulting in the formation of α-aryl(alkyl)thio-γ,δ-unsaturated ketones upon facile [2,3]sigmatropic rearrangements.
Co-reporter:Yanzhao Wang, Longwu Ye and Liming Zhang
Chemical Communications 2011 - vol. 47(Issue 27) pp:NaN7817-7817
Publication Date(Web):2011/06/03
DOI:10.1039/C1CC12212F
The first gold-catalyzed addition of N-arylhydroxylamines to aliphatic terminal alkynes is developed to access O-alkenyl-N-arylhydroxylamines, which undergo facile in situ sequential 3,3-rearrangements and cyclodehydrations to afford 2-alkylindoles with regiospecificity and under exceptionally mild reaction conditions.
Co-reporter:Li Cui, Longwu Ye and Liming Zhang
Chemical Communications 2010 - vol. 46(Issue 19) pp:NaN3353-3353
Publication Date(Web):2010/03/30
DOI:10.1039/C001314E
A surprisingly efficient synthesis of azepan-4-ones via a two-step [5+2] annulation is developed. This reaction involves a key gold catalysis and shows generally high regioselectivities and good to excellent diastereoselectivities.
Co-reporter:Yanzhao Wang, Biao Lu and Liming Zhang
Chemical Communications 2010 - vol. 46(Issue 48) pp:NaN9181-9181
Publication Date(Web):2010/10/29
DOI:10.1039/C0CC03669B
A gold-catalyzed synthesis of 1-bromo/chloro-2-carboxy-1,3-dienes is developed using propargylic carboxylates containing halogenated alkynes as substrates. The reaction is highly diastereoselective, and the halogen atom at the alkyne terminus selectively promotes a 1,2-acyloxy migration. The diene products participate in the Diels–Alder and cross-coupling reactions.
Co-reporter:Wen-Ting Wu, Ren-Qi Xu, Liming Zhang and Shu-Li You
Chemical Science (2010-Present) 2016 - vol. 7(Issue 5) pp:NaN3431-3431
Publication Date(Web):2016/02/02
DOI:10.1039/C5SC04130A
A highly efficient, gold-catalyzed intramolecular dearomatization reaction of naphthols via 5-endo-dig cyclization is described. This facile and direct approach furnishes spirocarbocycles in excellent yields under mild conditions.
Co-reporter:Yanzhao Wang, Lianzhu Liu and Liming Zhang
Chemical Science (2010-Present) 2013 - vol. 4(Issue 2) pp:NaN746-746
Publication Date(Web):2012/12/05
DOI:10.1039/C2SC21333H
The Fischer indole synthesis is perhaps the most powerful method for indole preparation, but it often suffers from low regioselectivities with unsymmetrical aliphatic ketone substrates and strongly acidic conditions and is not suitable for α,β-unsaturated ketones. In this edge article, we disclose an efficient synthesis of N-protected indoles from N-arylhydroxamic acids/N-aryl-N-hydroxycarbamates and a variety of alkynes via cooperative gold and zinc catalysis. The zinc catalysis is similar to the related zinc ion catalysis in metalloenzymes such as human carbonic anhydrase II and substantially enhances the O-nucleophilicity of N-acylated hydroxylamine by forming the corresponding Zn chelates. The Zn chelates can attack gold-activated alkynes to form O-alkenyl-N-arylhydroxamates, which can undergo facile 3,3-sigmatropic rearrangements and subsequent cyclodehydrations to yield N-protected indole products. This new chemistry offers several important improvements over the Fischer indole synthesis: (a) the reaction conditions are mildly acidic and can tolerate sensitive groups such as Boc; (b) broader substrate scopes including substrates with pendant carbonyl groups (reactive in the Fischer chemistry) and alkyl chlorides; (c) better regioselectivities for the formation of 2-substituted indoles under much milder conditions; (d) 2-alkenylindoles can be prepared readily in good to excellent yields, for which Fischer chemistry could not be used; (e) with internal alkynes both steric and electronic controls are available for achieving good regioselectivities, while Fischer chemistry is in general problematic.
Co-reporter:Zhitong Zheng, Zhixun Wang, Youliang Wang and Liming Zhang
Chemical Society Reviews 2016 - vol. 45(Issue 16) pp:NaN4458-4458
Publication Date(Web):2016/01/19
DOI:10.1039/C5CS00887E
The two main strategies of gold-catalysed oxidative cyclisation are discussed in this tutorial. The first one employs nucleophilic oxidants as either internal or external nucleophiles. The inherently weak O-heteroatom bond in the oxidant enables the versatile reactivities of the initial gold-promoted adduct of the oxidant to alkyne, including its fragmentation into a highly reactive α-oxo gold carbene intermediate. The second features external oxidant-powered Au(I)/Au(III) catalysis, where the metal oxidation state changes during the catalytic cycle. These strategies have been applied toward the development of a variety of valuable synthetic transformations.
Co-reporter:Wen-Ting Wu, Liming Zhang and Shu-Li You
Chemical Society Reviews 2016 - vol. 45(Issue 6) pp:NaN1580-1580
Publication Date(Web):2016/01/22
DOI:10.1039/C5CS00356C
Phenols are widely used as starting materials in both industrial and academic society. Dearomatization reactions of phenols provide an efficient way to construct highly functionalized cyclohexadienones. The main challenge to make them asymmetric by catalytic methods is to control the selectivity while overcoming the loss of aromaticity. In this tutorial review, an up to date summary of recent progress in CADA reactions of phenol and aniline derivatives is presented.
Co-reporter:Weimin He, Longyong Xie, Yingying Xu, Jiannan Xiang and Liming Zhang
Organic & Biomolecular Chemistry 2012 - vol. 10(Issue 16) pp:NaN3171-3171
Publication Date(Web):2012/03/14
DOI:10.1039/C2OB25235J
α-Oxo gold carbenes generated via intermolecular oxidation of terminal alkynes are shown to be highly electrophilic and can effectively abstract halogen from halogenated solvents such as 1,2-dichloroethane or 1,2-dibromoethane. Chloro/bromomethyl ketones are prepared in moderate efficiencies in one step using Ph3PAuNTf2 as the catalyst and 8-methylquinoline N-oxide as the oxidant.
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dimethyl-](http://img.cochemist.com/ccimg/124700/124696-14-6.png)
dimethyl-](http://img.cochemist.com/ccimg/124700/124696-14-6_b.png)
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