Co-reporter:Xuan Huang, Tingshun Zhu, Zhijian Huang, Yuexia Zhang, Zhichao Jin, Giuseppe Zanoni, and Yonggui Robin Chi
Organic Letters November 17, 2017 Volume 19(Issue 22) pp:6188-6188
Publication Date(Web):November 7, 2017
DOI:10.1021/acs.orglett.7b03102
An N-heterocyclic carbene-catalyzed formal [5 + 5] reaction between enals and furanones that generates multisubstituted coumarins in a single step is reported. Five atoms in each of the substrates are involved in this catalytic process to form a benzene and a lactone ring. The power of the method is further demonstrated in metal-free total syntheses of several natural products (defucogilvocarcins M, E, and V) bearing coumarin as the key structural motif.
Co-reporter:Jian Cheng, Jun Sun, Jiekuan Yan, Song Yang, Pengcheng Zheng, Zhichao Jin, and Yonggui Robin Chi
The Journal of Organic Chemistry December 15, 2017 Volume 82(Issue 24) pp:13342-13342
Publication Date(Web):November 13, 2017
DOI:10.1021/acs.joc.7b02436
The metal-free catalytic functionalization of aromatic sp2-carbons and benzylic sp3-carbons remains challenging. Here we report a carbene-catalyzed functionalization of the 3-methyl sp3-carbon attached to 2-formyl-indoles. The reaction proceeds through an NHC-bound o-quinodimethane as the key intermediate generated from 2-formyl-3-methylindoles under oxidative conditions. Reactive ketones are found to be effective substrates to produce substituted hydropyrano[3,4-b]indoles in good to excellent yields.
Co-reporter:Yuexia Zhang;Zeng Rong Wong;Xingxing Wu;Sherman J. L. Lauw;Xuan Huang;Richard D. Webster
Chemical Communications 2017 vol. 53(Issue 1) pp:184-187
Publication Date(Web):2016/12/20
DOI:10.1039/C6CC08631D
Sulfoxides are important functional molecules. We develop a short-route (one-pot) synthesis of this class of molecules by reacting thiols with alkenes or alkynes under mild and metal-free conditions. N-Fluorobenzenesulfonimide (NFSI) is used to play dual roles: as a radical initiator for a thiol–ene/–yne reaction to form sulfide adducts, and as efficient oxidant for conversion of the sulfides formed in situ to sulfoxides. Over-oxidation of the sulfoxides to sulfones is avoided in our approach.
Co-reporter:Chengli Mou;Jichang Wu;Zhijian Huang;Jun Sun;Zhichao Jin
Chemical Communications 2017 vol. 53(Issue 100) pp:13359-13362
Publication Date(Web):2017/12/14
DOI:10.1039/C7CC08039E
A carbene-catalyzed LUMO activation of α,β-unsaturated alkyne esters is reported. This catalytic process allows for effective reactions of alkyne esters with enamides to synthesize functional pyridines via simple protocols. A previously unexplored unsaturated alkyne acyl azolium intermediate is involved in the key step of the reaction.
Co-reporter:Yuhuang Wang;Xingxing Wu
Chemical Communications 2017 vol. 53(Issue 87) pp:11952-11955
Publication Date(Web):2017/10/31
DOI:10.1039/C7CC07208B
A carbene-catalyzed cascade reaction is developed for the synthesis of multi-substituted indane derivatives. The reaction involves two sequential Michael-addition steps, of which the first step is enabled by an NHC-mediated radical process. This work demonstrates the synthetic potentials of NHC-mediated single-electron-transfer processes for efficient reactions and rapid synthesis.
Co-reporter:Yuhuang Wang, Yu Du, Xuan Huang, Xingxing Wu, Yuexia Zhang, Song Yang, and Yonggui Robin Chi
Organic Letters 2017 Volume 19(Issue 3) pp:
Publication Date(Web):January 25, 2017
DOI:10.1021/acs.orglett.6b03792
A carbene-catalyzed reductive 1,4-addition of nitrobenzyl bromides to nitroalkenes is disclosed. The reaction proceeds via a carbene-enabled single-electron-transfer process that generates radicals as key intermediates. The present study expands the potentials of carbene catalysis and offers unusual transformations for common substrates in organic synthesis.
Co-reporter:Yuexia Zhang;Xingxing Wu;Lin Hao;Zeng Rong Wong;Sherman J. L. Lauw;Song Yang;Richard D. Webster
Organic Chemistry Frontiers 2017 vol. 4(Issue 3) pp:467-471
Publication Date(Web):2017/02/28
DOI:10.1039/C6QO00738D
An unusual trimerization of enone via a formal [2 + 2 + 2] process is disclosed. The reaction is initiated by a radical process enabled by NaOtBu and N-heterocyclic carbene (NHC). Molecular oxygen (air) is involved in key steps of the radical intermediate formation and carbon–carbon bond cleavage in this trimerization reaction to form highly substituted cyclohexane derivatives. In previous studies, alkali metal tert-butoxides such as NaOtBu were mainly employed to generate radical intermediates from aryl halides. Here we provide a new avenue in using NaOtBu and combined NHC/NaOtBu to generate radical intermediates from enones for further reactions.
Co-reporter:Xingkuan Chen; Jacqueline Zi Mei Fong; Jianfeng Xu; Chengli Mou; Yunpeng Lu; Song Yang; Bao-An Song
Journal of the American Chemical Society 2016 Volume 138(Issue 23) pp:7212-7215
Publication Date(Web):May 24, 2016
DOI:10.1021/jacs.6b00406
Carbene-catalyzed reaction of carboxylic esters has the potential to offer effective synthetic solutions that cannot be readily achieved by using the more conventional aldehyde-type substrates. Here we report the first carbene-catalyzed dynamic kinetic resolution of α,α-disubstituted carboxylic esters with up to 99:1 er and 99% yield. The present study clearly illustrates the unique power of carbene-catalyzed reactions of readily available and easy to handle carboxylic esters.
Co-reporter:Zhijian Huang; Xuan Huang; Baosheng Li; Chengli Mou; Song Yang; Bao-An Song
Journal of the American Chemical Society 2016 Volume 138(Issue 24) pp:7524-7527
Publication Date(Web):June 10, 2016
DOI:10.1021/jacs.6b04624
A carbene-catalyzed desymmetrization of prochiral bisphenol compounds bearing remote P-stereogenic centers is disclosed. The catalytic reactions can be performed on gram scales with 1 mol % N-heterocyclic carbene (NHC) catalyst, providing efficient access to enantiomerically enriched P-stereogenic phosphinates. The chiral phosphinates prepared with our method can find widespread applications as asymmetric organic catalysts and ligands.
Co-reporter:Bao-Sheng Li, Yuhuang Wang, Rupert S. J. Proctor, Zhichao Jin and Yonggui Robin Chi
Chemical Communications 2016 vol. 52(Issue 53) pp:8313-8316
Publication Date(Web):08 Jun 2016
DOI:10.1039/C6CC03345H
The introduction of a chlorine atom to a carbon center in an enantioselective manner via conventional C–Cl bond formation is difficult. Here we report a new approach to this class of tertiary alkyl chlorides with high optical purities. Instead of forming a new C–Cl bond, our approach involves carbene-catalyzed desymmetrization of 2-chloro-1,3-diols as the key step to set up the chiral carbon center with excellent enantiomeric excess.
Co-reporter:Yuexia Zhang; Yu Du; Zhijian Huang; Jianfeng Xu; Xingxing Wu; Yuhuang Wang; Ming Wang; Song Yang; Richard D. Webster
Journal of the American Chemical Society 2015 Volume 137(Issue 7) pp:2416-2419
Publication Date(Web):February 4, 2015
DOI:10.1021/ja511371a
An N-heterocyclic carbene-catalyzed β-hydroxylation of enals is developed. The reaction goes through a pathway involving multiple radical intermediates, as supported by experimental observations. This oxidative single-electron-transfer reaction allows for highly enantioselective access to β-hydroxyl esters that are widely found in natural products and bioactive molecules.
Co-reporter:Tingshun Zhu; Chengli Mou; Baosheng Li; Marie Smetankova; Bao-An Song
Journal of the American Chemical Society 2015 Volume 137(Issue 17) pp:5658-5661
Publication Date(Web):April 24, 2015
DOI:10.1021/jacs.5b02219
An N-heterocyclic carbene (NHC) catalyzed domino reaction triggered by a δ-LUMO activation of α,β–γ,δ-diunsaturated enal has been developed for the formal [4 + 2] construction of multisubstituted arenes and 3-ylidenephthalide. These two products, formed in a highly chemo- and regioselective manner, were obtained via different catalytic pathways due to a simple change of the substrate. The activation of the remote δ-carbon of unsaturated aldehydes expands the synthetic potentials of NHC organocatalysis.
Co-reporter:Bao-Sheng Li, Yuhuang Wang, Zhichao Jin and Yonggui Robin Chi
Chemical Science 2015 vol. 6(Issue 10) pp:6008-6012
Publication Date(Web):20 Jul 2015
DOI:10.1039/C5SC01972A
The addition of an organic catalyst to the ketone moiety of a γ-mono-chloride substituted cyclobutenone destroys its stable, conjugated and nearly planar structure. The C–C bond in the resulting less stable anionic oxy-substituted non-planar intermediate is then activated. The breaking of one C–C single bond leads to a catalyst-bound intermediate that undergoes α-carbon selective reactions with azomethine imines to afford nitrogen-containing heterocyclic compounds with excellent diastereo- and enantio-selectivities. Our organocatalytic approach provides a new reaction pattern for C–C bond activation of cyclobutenones that is unavailable with transition metal catalysis. In addition, the present study with isothioureas as the organocatalysts expands the potential in using organocatalysts for C–C bond breaking and selective reactions.
Co-reporter:Dr. Jianfeng Xu;Xingkuan Chen;Dr. Ming Wang;Pengcheng Zheng;Bao-An Song;Dr. Yonggui Robin Chi
Angewandte Chemie 2015 Volume 127( Issue 17) pp:5250-5254
Publication Date(Web):
DOI:10.1002/ange.201412132
Abstract
A convergent, organocatalytic asymmetric aminomethylation of α,β-unsaturated aldehydes by N-heterocyclic carbene (NHC) and (in situ generated) Brønsted acid cooperative catalysis is disclosed. The catalytically generated conjugated acid from the base plays dual roles in promoting the formation of azolium enolate intermediate, formaldehyde-derived iminium ion (as an electrophilic reactant), and methanol (as a nucleophilic reactant). This redox-neutral strategy is suitable for the scalable synthesis of enantiomerically enriched β2-amino acids bearing various substituents.
Co-reporter:Peng-Cheng Zheng;Dr. Jiajia Cheng;Shihu Su;Zhichao Jin;Yu-Huang Wang;Dr. Song Yang;Lin-Hong Jin;Dr. Bao-An Song;Dr. Yonggui Robin Chi
Chemistry - A European Journal 2015 Volume 21( Issue 28) pp:9984-9987
Publication Date(Web):
DOI:10.1002/chem.201501632
Abstract
The reaction mechanism of the γ-carbon addition of enal to imine under oxidative N-heterocyclic carbene catalysis is studied experimentally. The oxidation, γ-carbon deprotonation, and nucleophilic addition of γ-carbon to imine were found to be facile steps. The results of our study also provide highly enantioselective access to tricyclic sulfonyl amides that exhibit interesting antimicrobial activities against X. oryzae, a bacterium that causes bacterial disease in rice growing.
Co-reporter:Dr. Jianfeng Xu;Xingkuan Chen;Dr. Ming Wang;Pengcheng Zheng;Bao-An Song;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2015 Volume 54( Issue 17) pp:5161-5165
Publication Date(Web):
DOI:10.1002/anie.201412132
Abstract
A convergent, organocatalytic asymmetric aminomethylation of α,β-unsaturated aldehydes by N-heterocyclic carbene (NHC) and (in situ generated) Brønsted acid cooperative catalysis is disclosed. The catalytically generated conjugated acid from the base plays dual roles in promoting the formation of azolium enolate intermediate, formaldehyde-derived iminium ion (as an electrophilic reactant), and methanol (as a nucleophilic reactant). This redox-neutral strategy is suitable for the scalable synthesis of enantiomerically enriched β2-amino acids bearing various substituents.
Co-reporter:Ming Wang ; Zhijian Huang ; Jianfeng Xu
Journal of the American Chemical Society 2014 Volume 136(Issue 4) pp:1214-1217
Publication Date(Web):January 14, 2014
DOI:10.1021/ja411110f
The first N-heterocyclic carbene (NHC)-catalyzed [3+4] cycloaddition of azomethine imines and enals is disclosed. Oxidative catalytic remote activation of enals affords 1,4-dipolarophile intermediates that react with 1,3-dipolar azomethine imines to generate dinitrogen-fused seven-membered heterocyclic products with high optical purities. Our approach also provides effective kinetic resolution of azomethine imines, in which the substrate chiral center that is remote from the NHC catalyst can be well resolved.
Co-reporter:Yu Du, Yuhuang Wang, Xin Li, Yaling Shao, Guohui Li, Richard D. Webster, and Yonggui Robin Chi
Organic Letters 2014 Volume 16(Issue 21) pp:5678-5681
Publication Date(Web):October 24, 2014
DOI:10.1021/ol5027415
An unprecedented N-heterocyclic carbene catalytic reductive β,β-carbon coupling of α,β-nitroalkenes, by using an organic substrate to mimic the one-electron oxidation role of the pyruvate ferredoxin oxidoreductase (PFOR) in living systems, has been developed. The reaction goes through a radical anion intermediate generated under a catalytic redox process. For the first time, the presence of radical anion intermediate in NHC organocatalysis is observed and clearly verified.
Co-reporter:Jianfeng Xu, Chengli Mou, Tingshun Zhu, Bao-An Song, and Yonggui Robin Chi
Organic Letters 2014 Volume 16(Issue 12) pp:3272-3275
Publication Date(Web):May 30, 2014
DOI:10.1021/ol501286e
A chemo- and enantioselective cross-aza-benzoin reaction between enals and isatin-derived ketimines is disclosed. The high chemoselectivity (of the acyl anion reaction over enal α- and β-carbon reactions) is enabled by the electronic and steric properties of the N-heterocyclic carbene organocatalyst.
Co-reporter:Dr. Zhenqian Fu;Dr. Ke Jiang;Dr. Tingshun Zhu;Dr. Jaume Torres;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2014 Volume 53( Issue 25) pp:6506-6510
Publication Date(Web):
DOI:10.1002/anie.201402620
Abstract
Organocatalytic ester activation is developed for a highly selective cascade reaction between saturated esters and amino enones. The reaction involves activation of the β-carbon atom of the ester as a key step. This method allows a single-step access to multicyclic oxoquinoline-type heterocycles with high enantiomeric ratios.
Co-reporter:Zhichao Jin;Shaojin Chen;Yuhuang Wang;Pengcheng Zheng;Dr. Song Yang;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2014 Volume 53( Issue 49) pp:13506-13509
Publication Date(Web):
DOI:10.1002/anie.201408604
Abstract
The first NHC-catalyzed functionalization of carboxylic anhydrides is described. In this reaction, the β carbon behaves as a nucleophilic carbon and undergoes asymmetric reactions with electrophiles. Anhydrides with challenging β-alkyl substituents work effectively.
Co-reporter:Dr. Zhenqian Fu;Dr. Ke Jiang;Dr. Tingshun Zhu;Dr. Jaume Torres;Dr. Yonggui Robin Chi
Angewandte Chemie 2014 Volume 126( Issue 25) pp:6624-6628
Publication Date(Web):
DOI:10.1002/ange.201402620
Abstract
Organocatalytic ester activation is developed for a highly selective cascade reaction between saturated esters and amino enones. The reaction involves activation of the β-carbon atom of the ester as a key step. This method allows a single-step access to multicyclic oxoquinoline-type heterocycles with high enantiomeric ratios.
Co-reporter:Junmin Zhang ; Chong Xing ; Bhoopendra Tiwari
Journal of the American Chemical Society 2013 Volume 135(Issue 22) pp:8113-8116
Publication Date(Web):May 20, 2013
DOI:10.1021/ja401511r
We disclose the first catalytic activation of carbohydrates as formaldehyde equivalents to generate acyl anions as one-carbon nucleophilic units for a Stetter reaction. The activation involves N-heterocyclic carbene (NHC)-catalyzed C–C bond cleavage of carbohydrates via a retro-benzoin-type process to generate the acyl anion intermediates. This Stetter reaction constitutes the first success in generating formal formaldehyde-derived acyl anions as one-carbon nucleophiles for non-self-benzoin processes. The renewable nature of carbohydrates, accessible from biomass, further highlights the practical potential of this fundamentally interesting catalytic activation.
Co-reporter:Wendy Wen Yi Leong, Xingkuan Chen and Yonggui Robin Chi
Green Chemistry 2013 vol. 15(Issue 6) pp:1505-1508
Publication Date(Web):09 Apr 2013
DOI:10.1039/C3GC40397A
Water is demonstrated as a suitable solvent for NHC-catalyzed reactions of enals. The use of D2O as a solvent allows for the effective incorporation of deuterium isotopes into organic molecules.
Co-reporter:Xingkuan Chen, Xinqiang Fang and Yonggui Robin Chi
Chemical Science 2013 vol. 4(Issue 6) pp:2613-2618
Publication Date(Web):11 Apr 2013
DOI:10.1039/C3SC50666E
The first successful generation of cis-homoenolate equivalents from cis-enals under the catalysis of N-heterocyclic carbenes (NHCs) has been realized. The cis-homoenolate intermediates undergo effective reactions with α,β-unsaturated imines to afford chiral cyclic ketone products. Compared to the trans-enals, cis-enals show different stereoselectivities and new reactivity patterns.
Co-reporter:Lin Hao, Shaojin Chen, Jianfeng Xu, Bhoopendra Tiwari, Zhenqian Fu, Tong Li, Jieyan Lim, and Yonggui Robin Chi
Organic Letters 2013 Volume 15(Issue 19) pp:4956-4959
Publication Date(Web):September 26, 2013
DOI:10.1021/ol4021805
Asymmetric functionalization of alkylacetic esters and their derivatives is traditionally achieved via preformed enolates with chiral auxiliaries. Catalytic versions of such transformations are attractive but challenging. A direct catalytic activation of simple alkylacetic esters via N-heterocyclic carbene organocatalysts to generate chiral enolate intermediates for highly enantioselective reactions is reported.
Co-reporter:Junming Mo, Ruojie Yang, Xingkuan Chen, Bhoopendra Tiwari, and Yonggui Robin Chi
Organic Letters 2013 Volume 15(Issue 1) pp:50-53
Publication Date(Web):December 18, 2012
DOI:10.1021/ol303035r
A direct α-functionalization of simple aldehydes under N-Heterocyclic Carbene (NHC) catalysis and direct generation of ester enolate equivalents from nonfunctionalized aldehydes are disclosed. The catalysis involves selective enolate generation from an oxidatively generated NHC-bounded ester intermediate as a key step. The ester enolate intermediates undergo stereoselective reactions with enones and trifluoromethyl ketones.
Co-reporter:Shaojin Chen, Lin Hao, Yuexia Zhang, Bhoopendra Tiwari, and Yonggui Robin Chi
Organic Letters 2013 Volume 15(Issue 22) pp:5822-5825
Publication Date(Web):October 25, 2013
DOI:10.1021/ol402877n
An NHC-catalyzed activation of acetic esters to afford enolate intermediates is disclosed. The catalytically generated triazolium enolate intermediates serve as two-carbon nucleophiles that undergo highly enantioselective reactions with enones and α,β-unsaturated imines to give α-unsubstituted δ-lactones and lactams, respectively.
Co-reporter:Zhenqian Fu, Hui Sun, Shaojin Chen, Bhoopendra Tiwari, Guohui Li and Yonggui Robin Chi
Chemical Communications 2013 vol. 49(Issue 3) pp:261-263
Publication Date(Web):09 Nov 2012
DOI:10.1039/C2CC36564B
A substrate-independent selective generation of enolates over homoenolate equivalents in NHC-catalyzed reactions of enals and chalcones is disclosed. Acid co-catalysts play vital roles in control of the reaction pathways, allowing for individual access to diverse products from identical substrates.
Co-reporter:Jianfeng Xu, Zhichao Jin, and Yonggui Robin Chi
Organic Letters 2013 Volume 15(Issue 19) pp:5028-5031
Publication Date(Web):September 25, 2013
DOI:10.1021/ol402358k
The direct γ-carbon functionalization of α,β-unsaturated esters via N-Heterocyclic Carbene (NHC) catalysis is disclosed. This catalytically generated nucleophilic γ-carbon undergoes highly enantioselective additions to hydrazones. The resulting δ-lactam products can be readily transformed to optically enriched pipecolic acid derivatives.
Co-reporter:Zhichao Jin;Dr. Jianfeng Xu;Dr. Song Yang;Dr. Bao-An Song;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2013 Volume 52( Issue 47) pp:12354-12358
Publication Date(Web):
DOI:10.1002/anie.201305023
Co-reporter:Dr. Jiajia Cheng;Zhijian Huang ;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2013 Volume 52( Issue 33) pp:8592-8596
Publication Date(Web):
DOI:10.1002/anie.201303247
Co-reporter:Junming Mo;Liang Shen ;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2013 Volume 52( Issue 33) pp:8588-8591
Publication Date(Web):
DOI:10.1002/anie.201302152
Co-reporter:Dr. Jiajia Cheng;Zhijian Huang ;Dr. Yonggui Robin Chi
Angewandte Chemie 2013 Volume 125( Issue 33) pp:8754-8758
Publication Date(Web):
DOI:10.1002/ange.201303247
Co-reporter:Junming Mo;Liang Shen ;Dr. Yonggui Robin Chi
Angewandte Chemie 2013 Volume 125( Issue 33) pp:8750-8753
Publication Date(Web):
DOI:10.1002/ange.201302152
Co-reporter:Xingkuan Chen;Dr. Song Yang;Dr. Bao-An Song;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2013 Volume 52( Issue 42) pp:11134-11137
Publication Date(Web):
DOI:10.1002/anie.201305861
Co-reporter:Junming Mo ; Xingkuan Chen
Journal of the American Chemical Society 2012 Volume 134(Issue 21) pp:8810-8813
Publication Date(Web):May 9, 2012
DOI:10.1021/ja303618z
An oxidative γ-functionalization of enals under N-heterocyclic carbene (NHC) catalysis to give unsaturated δ-lactones is disclosed. Enantioselectivity control involving the relatively remote enal γ-carbon was achieved via Lewis acid [Sc(OTf)3 or combined Sc(OTf)3/Mg(OTf)2] and NHC cooperative catalysis.
Co-reporter:Hui Lv, Bhoopendra Tiwari, Junming Mo, Chong Xing, and Yonggui Robin Chi
Organic Letters 2012 Volume 14(Issue 21) pp:5412-5415
Publication Date(Web):October 12, 2012
DOI:10.1021/ol302475g
An N-heterocyclic carbene (NHC)-catalyzed annulation reaction of isatin N-Boc ketimines and enals is developed for the synthesis of spirocyclic oxindole-γ-lactams bearing one quaternary chiral center in good yields and excellent stereoselectivities (up to >20:1 dr and 99% ee).
Co-reporter:Zhichao Jin, Ruojie Yang, Yu Du, Bhoopendra Tiwari, Rakesh Ganguly, and Yonggui Robin Chi
Organic Letters 2012 Volume 14(Issue 12) pp:3226-3229
Publication Date(Web):2017-2-22
DOI:10.1021/ol3013588
The first chiral phosphine-catalyzed activation of acrylates for intramolecular formal [2 + 4] reactions with unsaturated imines is described. The catalytic reactions afford N-heterocycles with exceptionally high diastereo- and enantioselectivities. The [2 + 4] products are amenable for further transformations to useful molecules such as chiral piperidines and multicyclic structures.
Co-reporter:Qiang Tang, Xingkuan Chen, Bhoopendra Tiwari, and Yonggui Robin Chi
Organic Letters 2012 Volume 14(Issue 7) pp:1922-1925
Publication Date(Web):March 28, 2012
DOI:10.1021/ol300591z
A direct coupling of unprotected indoles and α-halo ketones via in situ generated oxyallyl cation intermediates is described. The reactions efficiently afford α-indole carbonyl compounds with good to quantitative yields.
Co-reporter:Lin Hao, Yu Du, Hui Lv, Xingkuan Chen, Huishen Jiang, Yaling Shao, and Yonggui Robin Chi
Organic Letters 2012 Volume 14(Issue 8) pp:2154-2157
Publication Date(Web):April 9, 2012
DOI:10.1021/ol300676w
The first N-Heterocyclic Carbene (NHC) mediated activation of stable carboxylate esters to generate enolate intermediates is disclosed. The catalytically generated arylacetic ester enolates undergo enantioselective reactions with α,β-unsaturated imines.
Co-reporter:Kun Jiang, Bhoopendra Tiwari, and Yonggui Robin Chi
Organic Letters 2012 Volume 14(Issue 9) pp:2382-2385
Publication Date(Web):April 23, 2012
DOI:10.1021/ol3008028
A diastereoselective access to β-lactam fused spirocyclic oxindoles and related compounds bearing all carbon spiro centers is described. This N-heterocyclic carbene-catalyzed process employed challenging β,β-disubstituted α,β-unsaturated imines to react with enals.
Co-reporter:Dr. Junmin Zhang;Dr. Bhoopendra Tiwari;Chong Xing;Xingkuan Chen ;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2012 Volume 51( Issue 15) pp:3649-3652
Publication Date(Web):
DOI:10.1002/anie.201109054
Co-reporter:Dr. Bhoopendra Tiwari;Dr. Junmin Zhang ;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2012 Volume 51( Issue 8) pp:1911-1914
Publication Date(Web):
DOI:10.1002/anie.201107473
Co-reporter:Dr. Bhoopendra Tiwari;Dr. Junmin Zhang ;Dr. Yonggui Robin Chi
Angewandte Chemie 2012 Volume 124( Issue 8) pp:1947-1950
Publication Date(Web):
DOI:10.1002/ange.201107473
Co-reporter:Dr. Junmin Zhang;Dr. Bhoopendra Tiwari;Chong Xing;Xingkuan Chen ;Dr. Yonggui Robin Chi
Angewandte Chemie 2012 Volume 124( Issue 15) pp:3709-3712
Publication Date(Web):
DOI:10.1002/ange.201109054
Co-reporter:Hui Lv, Junming Mo, Xinqiang Fang, and Yonggui Robin Chi
Organic Letters 2011 Volume 13(Issue 19) pp:5366-5369
Publication Date(Web):August 30, 2011
DOI:10.1021/ol202250s
Highly enantioselective (formal) hetero-Diels–Alder reactions between chalcones and formylcyclopropanes are disclosed. The challenging N-heterocyclic carbene (NHC)-bounded enolate intermediates from formylcyclopropanes were captured for new C–C bond forming reactions. The reaction products were obtained with high diastereo- and enantioselectivities and could be easily transformed to optically pure multisubstituted cyclohexane derivatives.
Co-reporter:Chong Xing;Dr. Hui Sun;Dr. Junmin Zhang;Dr. Guohui Li;Dr. Yonggui Robin Chi
Chemistry - A European Journal 2011 Volume 17( Issue 44) pp:12272-12275
Publication Date(Web):
DOI:10.1002/chem.201102623
Co-reporter:Dr. Xinqiang Fang;Kun Jiang;Chong Xing;Lin Hao ;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2011 Volume 50( Issue 8) pp:1910-1913
Publication Date(Web):
DOI:10.1002/anie.201007144
Co-reporter:Dr. Xinqiang Fang;Xingkuan Chen;Dr. Hui Lv ;Dr. Yonggui Robin Chi
Angewandte Chemie International Edition 2011 Volume 50( Issue 49) pp:11782-11785
Publication Date(Web):
DOI:10.1002/anie.201105812
Co-reporter:Dr. Xinqiang Fang;Xingkuan Chen;Dr. Hui Lv ;Dr. Yonggui Robin Chi
Angewandte Chemie 2011 Volume 123( Issue 49) pp:11986-11989
Publication Date(Web):
DOI:10.1002/ange.201105812
Co-reporter:Dr. Xinqiang Fang;Kun Jiang;Chong Xing;Lin Hao ;Dr. Yonggui Robin Chi
Angewandte Chemie 2011 Volume 123( Issue 8) pp:1950-1953
Publication Date(Web):
DOI:10.1002/ange.201007144
Co-reporter:Bao-Sheng Li, Yuhuang Wang, Rupert S. J. Proctor, Zhichao Jin and Yonggui Robin Chi
Chemical Communications 2016 - vol. 52(Issue 53) pp:NaN8316-8316
Publication Date(Web):2016/06/08
DOI:10.1039/C6CC03345H
The introduction of a chlorine atom to a carbon center in an enantioselective manner via conventional C–Cl bond formation is difficult. Here we report a new approach to this class of tertiary alkyl chlorides with high optical purities. Instead of forming a new C–Cl bond, our approach involves carbene-catalyzed desymmetrization of 2-chloro-1,3-diols as the key step to set up the chiral carbon center with excellent enantiomeric excess.
Co-reporter:Xingkuan Chen, Xinqiang Fang and Yonggui Robin Chi
Chemical Science (2010-Present) 2013 - vol. 4(Issue 6) pp:NaN2618-2618
Publication Date(Web):2013/04/11
DOI:10.1039/C3SC50666E
The first successful generation of cis-homoenolate equivalents from cis-enals under the catalysis of N-heterocyclic carbenes (NHCs) has been realized. The cis-homoenolate intermediates undergo effective reactions with α,β-unsaturated imines to afford chiral cyclic ketone products. Compared to the trans-enals, cis-enals show different stereoselectivities and new reactivity patterns.
Co-reporter:Zhenqian Fu, Hui Sun, Shaojin Chen, Bhoopendra Tiwari, Guohui Li and Yonggui Robin Chi
Chemical Communications 2013 - vol. 49(Issue 3) pp:NaN263-263
Publication Date(Web):2012/11/09
DOI:10.1039/C2CC36564B
A substrate-independent selective generation of enolates over homoenolate equivalents in NHC-catalyzed reactions of enals and chalcones is disclosed. Acid co-catalysts play vital roles in control of the reaction pathways, allowing for individual access to diverse products from identical substrates.
Co-reporter:Lin Hao, Xingkuan Chen, Shaojin Chen, Ke Jiang, Jaume Torres and Yonggui Robin Chi
Inorganic Chemistry Frontiers 2014 - vol. 1(Issue 2) pp:
Publication Date(Web):
DOI:10.1039/C3QO00045A
Co-reporter:Yuexia Zhang, Xingxing Wu, Lin Hao, Zeng Rong Wong, Sherman J. L. Lauw, Song Yang, Richard D. Webster and Yonggui Robin Chi
Inorganic Chemistry Frontiers 2017 - vol. 4(Issue 3) pp:
Publication Date(Web):
DOI:10.1039/C6QO00738D
Co-reporter:Bao-Sheng Li, Yuhuang Wang, Zhichao Jin and Yonggui Robin Chi
Chemical Science (2010-Present) 2015 - vol. 6(Issue 10) pp:NaN6012-6012
Publication Date(Web):2015/07/20
DOI:10.1039/C5SC01972A
The addition of an organic catalyst to the ketone moiety of a γ-mono-chloride substituted cyclobutenone destroys its stable, conjugated and nearly planar structure. The C–C bond in the resulting less stable anionic oxy-substituted non-planar intermediate is then activated. The breaking of one C–C single bond leads to a catalyst-bound intermediate that undergoes α-carbon selective reactions with azomethine imines to afford nitrogen-containing heterocyclic compounds with excellent diastereo- and enantio-selectivities. Our organocatalytic approach provides a new reaction pattern for C–C bond activation of cyclobutenones that is unavailable with transition metal catalysis. In addition, the present study with isothioureas as the organocatalysts expands the potential in using organocatalysts for C–C bond breaking and selective reactions.
Co-reporter:Yuexia Zhang, Zeng Rong Wong, Xingxing Wu, Sherman J. L. Lauw, Xuan Huang, Richard D. Webster and Yonggui Robin Chi
Chemical Communications 2017 - vol. 53(Issue 1) pp:NaN187-187
Publication Date(Web):2016/11/29
DOI:10.1039/C6CC08631D
Sulfoxides are important functional molecules. We develop a short-route (one-pot) synthesis of this class of molecules by reacting thiols with alkenes or alkynes under mild and metal-free conditions. N-Fluorobenzenesulfonimide (NFSI) is used to play dual roles: as a radical initiator for a thiol–ene/–yne reaction to form sulfide adducts, and as efficient oxidant for conversion of the sulfides formed in situ to sulfoxides. Over-oxidation of the sulfoxides to sulfones is avoided in our approach.
![Carbamic acid, N-[5-bromo-1,2-dihydro-2-oxo-1-(phenylmethyl)-3H-indol-3-ylidene]-, 1,1-dimethylethyl ester](/data/chemimg/3741700/1426931-81-8.png)
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![Carbamic acid, N-[5-chloro-1,2-dihydro-2-oxo-1-(phenylmethyl)-3H-indol-3-ylidene]-, 1,1-dimethylethyl ester](/data/chemimg/3741700/1426931-80-7.png)
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![Carbamic acid, N-[5-fluoro-1,2-dihydro-2-oxo-1-(phenylmethyl)-3H-indol-3-ylidene]-, 1,1-dimethylethyl ester](/data/chemimg/3741700/1426931-79-4.png)
![Carbamic acid, N-[5-fluoro-1,2-dihydro-2-oxo-1-(phenylmethyl)-3H-indol-3-ylidene]-, 1,1-dimethylethyl ester](/data/chemimg/3741700/1426931-79-4_b.png)
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![Carbamic acid, N-[1,2-dihydro-2-oxo-1-(2-propen-1-yl)-3H-indol-3-ylidene]-, 1,1-dimethylethyl ester](/data/chemimg/3741600/1402155-99-0_b.png)
![(2S,6S)-2,6-Di-tert-butyl-2,3,5,6-tetrahydro-1H-imidazo[1,2-a]imidazole](http://img.cochemist.com/ccimg/877800/877773-38-1.png)
![(2S,6S)-2,6-Di-tert-butyl-2,3,5,6-tetrahydro-1H-imidazo[1,2-a]imidazole](http://img.cochemist.com/ccimg/877800/877773-38-1_b.png)
![(5AR,10BS)-(+)-5A,10B-DIHYDRO-2-(PENTAFLUOROPHENYL)-4H,6H-INDENO[2,1-B][1,2,4]TRIZOLO[4,3-D][1,4]OXAZINIUM TETRAFLUOROBORATE](http://img.cochemist.com/ccimg/872200/872143-57-2.png)
![(5AR,10BS)-(+)-5A,10B-DIHYDRO-2-(PENTAFLUOROPHENYL)-4H,6H-INDENO[2,1-B][1,2,4]TRIZOLO[4,3-D][1,4]OXAZINIUM TETRAFLUOROBORATE](http://img.cochemist.com/ccimg/872200/872143-57-2_b.png)
![1,3-Dioxolane, 2-[3-(bromomethyl)phenyl]-](http://img.cochemist.com/ccimg/140700/140639-95-8.png)
![1,3-Dioxolane, 2-[3-(bromomethyl)phenyl]-](http://img.cochemist.com/ccimg/140700/140639-95-8_b.png)
![Cyclohexane, [(1E)-2-nitroethenyl]-](http://img.cochemist.com/ccimg/132900/132839-80-6.png)
![Cyclohexane, [(1E)-2-nitroethenyl]-](http://img.cochemist.com/ccimg/132900/132839-80-6_b.png)
dimethyl-, (Z)-](/data/chemimg/1083700/132549-08-7.png)
dimethyl-, (Z)-](/data/chemimg/1083700/132549-08-7_b.png)
![Butanoic acid, 2-[(4-methylphenyl)methylene]-3-oxo-, methyl ester](http://img.cochemist.com/ccimg/107700/107634-95-7.png)
![Butanoic acid, 2-[(4-methylphenyl)methylene]-3-oxo-, methyl ester](http://img.cochemist.com/ccimg/107700/107634-95-7_b.png)
![Butanoic acid, 2-[(4-methoxyphenyl)methylene]-3-oxo-, methyl ester](http://img.cochemist.com/ccimg/106600/106521-81-7.png)
![Butanoic acid, 2-[(4-methoxyphenyl)methylene]-3-oxo-, methyl ester](http://img.cochemist.com/ccimg/106600/106521-81-7_b.png)
![2-PROPENAL, 3-[4-(METHOXYMETHOXY)PHENYL]-, (E)-](http://img.cochemist.com/ccimg/84200/84184-57-6.png)
![2-PROPENAL, 3-[4-(METHOXYMETHOXY)PHENYL]-, (E)-](http://img.cochemist.com/ccimg/84200/84184-57-6_b.png)
![BENZENE, [(1E)-3-BROMO-2-METHYL-1-PROPENYL]-](http://img.cochemist.com/ccimg/83200/83126-01-6.png)
![BENZENE, [(1E)-3-BROMO-2-METHYL-1-PROPENYL]-](http://img.cochemist.com/ccimg/83200/83126-01-6_b.png)
![Benzoic acid, 4-[(1E)-3-oxo-1-propen-1-yl]-, methyl ester](/data/chemimg/709300/78024-60-9.png)
![Benzoic acid, 4-[(1E)-3-oxo-1-propen-1-yl]-, methyl ester](/data/chemimg/709300/78024-60-9_b.png)
![2-[4-(BROMOMETHYL)PHENYL]-1,3-DIOXOLANE](http://img.cochemist.com/ccimg/74600/74508-89-7.png)
![2-[4-(BROMOMETHYL)PHENYL]-1,3-DIOXOLANE](http://img.cochemist.com/ccimg/74600/74508-89-7_b.png)
![Phosphine oxide, [2-(bromomethyl)phenyl]diphenyl-](/data/chemimg/1143600/68718-85-4.png)
![Phosphine oxide, [2-(bromomethyl)phenyl]diphenyl-](/data/chemimg/1143600/68718-85-4_b.png)
![2-Propenal,3-[4-(acetyloxy)-3-methoxyphenyl]-](http://img.cochemist.com/ccimg/65500/65401-83-4.png)
![2-Propenal,3-[4-(acetyloxy)-3-methoxyphenyl]-](http://img.cochemist.com/ccimg/65500/65401-83-4_b.png)
![1,3-Propanedione, 2-[(4-chlorophenyl)methylene]-1,3-diphenyl-](http://img.cochemist.com/ccimg/59900/59832-41-6.png)
![1,3-Propanedione, 2-[(4-chlorophenyl)methylene]-1,3-diphenyl-](http://img.cochemist.com/ccimg/59900/59832-41-6_b.png)
![Benzene, [(1E)-3-bromo-1-methyl-1-propen-1-yl]-](/data/chemimg/3760200/39171-59-0.png)
![Benzene, [(1E)-3-bromo-1-methyl-1-propen-1-yl]-](/data/chemimg/3760200/39171-59-0_b.png)
![1H-Indole-2,3-dione, 1-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/31600/31541-32-9.png)
![1H-Indole-2,3-dione, 1-[(4-methoxyphenyl)methyl]-](http://img.cochemist.com/ccimg/31600/31541-32-9_b.png)
![Pyridine, 3-[(1E)-2-nitroethenyl]-](/data/chemimg/1797700/22568-11-2.png)
![Pyridine, 3-[(1E)-2-nitroethenyl]-](/data/chemimg/1797700/22568-11-2_b.png)
![2,8-Dimethyl-2,3,4,4a,5,9b-hexahydro-1H-pyrido[4,3-b]indole](http://img.cochemist.com/ccimg/17500/17411-19-7.png)
![2,8-Dimethyl-2,3,4,4a,5,9b-hexahydro-1H-pyrido[4,3-b]indole](http://img.cochemist.com/ccimg/17500/17411-19-7_b.png)
![Benzene, [(1E)-1-methyl-2-nitroethenyl]-](/data/chemimg/1737100/15241-24-4.png)
![Benzene, [(1E)-1-methyl-2-nitroethenyl]-](/data/chemimg/1737100/15241-24-4_b.png)
![Hexanamide,N-[(4-methylphenyl)sulfonyl]-](http://img.cochemist.com/ccimg/1800/1788-15-4.png)
![Hexanamide,N-[(4-methylphenyl)sulfonyl]-](http://img.cochemist.com/ccimg/1800/1788-15-4_b.png)
![Carbamic acid, N-[1,2-dihydro-2-oxo-1-(phenylmethyl)-3H-indol-3-ylidene]-, 1,1-dimethylethyl ester](/data/chemimg/3741500/1373942-84-7.png)
![Carbamic acid, N-[1,2-dihydro-2-oxo-1-(phenylmethyl)-3H-indol-3-ylidene]-, 1,1-dimethylethyl ester](/data/chemimg/3741500/1373942-84-7_b.png)
![(5aR,10bS)-5a,10b-Dihydro-2-(2,4,6-trimethylphenyl)-4H,6H-indeno[2,1-b][1,2,4]triazolo[4,3-d][1,4]oxazinium Tetrafluoroborate](/data/chemimg/925706-31-6.png)
![(5aR,10bS)-5a,10b-Dihydro-2-(2,4,6-trimethylphenyl)-4H,6H-indeno[2,1-b][1,2,4]triazolo[4,3-d][1,4]oxazinium Tetrafluoroborate](/data/chemimg/925706-31-6_b.png)
