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
A Facile Synthesis of 2H-Chromenes and 9-Functionalized Phenanthrenes through Reactions between α,β-Unsaturated Compounds and Arynes
作者:Tiexin Zhang、Xian Huang、and Luling Wu
DOI:10.1002/ejoc.201200042
日期:2012.6
Facile syntheses of 2H-chromenes or 9-functionalizedphenanthrenes under mild conditions in moderate to good yields have been developed. They each involve annulations of arynes with α,β-unsaturatedcompounds bearing different electron-withdrawing groups (EWGs). Depending on the natures of the different EWGs, the reactions proceed by different pathways: enals react with arynesthrough a tandem [2+2]
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
Polyhalides as Efficient and Mild Oxidants for Oxidative Carbene Organocatalysis by Radical Processes
作者:Xingxing Wu、Yuexia Zhang、Yuhuang Wang、Jie Ke、Martin Jeret、Rambabu N. Reddi、Song Yang、Bao-An Song、Yonggui Robin Chi
DOI:10.1002/anie.201611692
日期:2017.3.6
Simple and inexpensive polyhalides (CCl4 and C2Cl6) have been found to be effective and versatile oxidants in removing electrons from Breslow intermediates under N‐heterocyclic carbene (NHC) catalysis. This oxidative reaction involves multiple single‐electron‐transfer (SET) processes and several radical intermediates. The α, β, and γ‐carbon atoms of aldehydes and enals could be readily functionalized