Oxidative γ-Addition of Enals to Trifluoromethyl Ketones: Enantioselectivity Control via Lewis Acid/N-Heterocyclic Carbene Cooperative Catalysis
作者:Junming Mo、Xingkuan Chen、Yonggui Robin Chi
DOI:10.1021/ja303618z
日期:2012.5.30
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 cooperativecatalysis.
Carbene-catalyzed enal γ-carbon addition to α-ketophosphonates for enantioselective access to bioactive 2-pyranylphosphonates
作者:Jun Sun、Fangcheng He、Zhongyao Wang、Dingwu Pan、Pengcheng Zheng、Chengli Mou、Zhichao Jin、Yonggui Robin Chi
DOI:10.1039/c8cc03017k
日期:——
A carbene-catalyzed enantioselective [4+2] cycloaddition reaction between α,β-unsaturated aldehydes and α-ketophosphonates is developed. The reaction affords chiral 2-pyranylphosphonates with excellent enantioselectivities. The optically enriched phosphonate products bear multiple functional groups, including unsaturated lactone and phosphonate moieties that often lead to unique bio-activities. Preliminary
Carbene-Catalyzed Formal [3+3] Cycloaddition Reaction for Access to Substituted 2-Phenylbenzothiazoles
作者:Zhibin Ni、Chengli Mou、Xun Zhu、Puying Qi、Song Yang、Yonggui Robin Chi、Zhichao Jin
DOI:10.1002/ejoc.201901773
日期:2020.1.31
carbene‐catalyzed oxidative cycloadditionreaction is developed for efficient access to multi‐functionalized 2‐phenylbenzothiazoles. A broad scope of heavily substituted arenes bearing 2‐benzothiazole groups have been prepared in good to excellent yields. The remote C(sp2)–H bond in the substituted arene products can be regioselectively activated by Pd catalysts with the direction of the 2‐benzothiazole groups
In contrast to well‐established asymmetric hydrogenation reactions, enantioselective protonation is an orthogonal approach for creating highly valuable methine chiral centers under redox‐neutral conditions. Reported here is the highly enantio‐ and diastereoselective hydrofluorination of enals by an asymmetric β‐protonation/α‐fluorination cascade catalyzed by N‐heterocyclic carbenes (NHCs). The two
Carbene-Catalyzed Formal [5 + 5] Reaction for Coumarin Construction and Total Synthesis of Defucogilvocarcins
作者:Xuan Huang、Tingshun Zhu、Zhijian Huang、Yuexia Zhang、Zhichao Jin、Giuseppe Zanoni、Yonggui Robin Chi
DOI:10.1021/acs.orglett.7b03102
日期:2017.11.17
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