在温和的反应条件下,简单的卤代酚与α,β-不饱和烯烃成功实现了脱芳构化/螺环化过程。这种转化解决了 SE Ar工艺引起的苯酚支架(6π-电子)脱芳构化转化中的化学选择性问题,从而能够以高产率构建含有连续四元全碳中心的通用环己二烯酮框架。进一步的研究为该过程提供了有价值的见解,揭示了脱溴/螺环化是通过 S RN 1 途径发生的。
Direct Sulfide-Catalyzed Enantioselective Cyclopropanations of Electron-Deficient Dienes and Bromides
作者:Qing-Zhu Li、Xiang Zhang、Rong Zeng、Qing-Song Dai、Yue Liu、Xu-Dong Shen、Hai-Jun Leng、Kai-Chuan Yang、Jun-Long Li
DOI:10.1021/acs.orglett.8b01537
日期:2018.6.15
A catalytic highly regioselective, diastereoselective, and enantioselective cyclopropanation of electron-deficient dienes and bromides via direct sulfide organocatalysis is reported. A variety of vinylcyclopropanes featuring a quaternary chiral center were synthesized in up to 99% yield and up to 98:2 enantiomeric ratio (er). These products could be facilely transformed to various interesting molecules
Heterogeneous Bifunctional Catalytic, Chemo-, Regio- and Enantioselective Cascade Inverse Electron Demand Diels-Alder Reaction
作者:Xianxing Jiang、Hao Zhu、Xiaomei Shi、Yuan Zhong、Yanfeng Li、Rui Wang
DOI:10.1002/adsc.201201038
日期:2013.1.25
We present a bifunctionalcatalytic, chemo-, regio- and enantioselectiveinverseelectrondemandDiels–Alderreaction (IEDDAR) cascade of a variety of methylenebut-3-enoates with azlactones at high levels of yield and enantioselectivity (up to 99% yield, and >99% ee) via a dual HOMOdienophiles and LUMOdienes activated pathway using a heterogeneouscatalytic system. Meanwhile, a novel MNPs-supported
Phosphine-catalyzed [4+1] annulation of 1,3-(aza)dienes with maleimides: highly efficient construction of azaspiro[4.4]nonenes
作者:Mei Yang、Tianyi Wang、Shixuan Cao、Zhengjie He
DOI:10.1039/c4cc05624h
日期:——
Phosphine-catalyzed [4+1] annulation of electron-deficient 1,3-dienes or 1,3-azadienes with maleimides has been successfully developed under very mild conditions, providing a convenient and highly efficient method for constructing 2-azaspiro[4.4]nonenes and 1,7-diazaspiro[4.4]nonenes. This reaction represents the first example of [4+1] cyclization between electron-deficient 4pi-conjugated systems and
A PPh3 mediated reductive annulation reactionbetweenisatins and 4,4-dicyano-2-methylenebut-3-enoates was developed. The reaction provided an alternative method for constructing five- and three-membered all-carbon spirooxindole compounds. Lithium chloride as a Lewis acid played a key role in the synthesis of spirocyclopentenyl oxindole compounds.
PPh3-catalyzed synthesis of dicyano-2-methylenebut-3-enoates as efficient dienes in catalytic asymmetric inverse-electron-demand Diels–Alder reaction
作者:Xianxing Jiang、Dan Fu、Xiaomei Shi、Shoulei Wang、Rui Wang
DOI:10.1039/c1cc12834e
日期:——
We present here the synthesis of dicyano-2-methylenebut-3-enoates as novel Diels-Alderdienes through an efficient PPh(3)-catalyzed strategy, and an unprecedented PPh(3)-catalyzed addition/all-carbon-based asymmetric inverse-electron-demand Diels-Alder sequence reaction is disclosed for the first time.