Direct Noncovalent Activation of ,-Unsaturated Aldehydes for the Stereodivergent Synthesis of Substituted Cyclohexenes
Direct Noncovalent Activation of ,-Unsaturated Aldehydes for the Stereodivergent Synthesis of Substituted Cyclohexenes
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α,β-不饱和醛的直接非共价活化用于立体发散合成取代环己烯
DOI：
10.1002/chem.201701315
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Xu Peng Fei
中科院分区：
文献类型：
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作者：
Xie Ji Kang;Wang Yang;Lin Jun Bing;Ren Xiao Rui;Xu Peng Fei
实现了使用双官能布朗斯台德碱催化剂的α-芳基α，β-不饱和醛的HOMO-升高非共价活化。催化生成的二烯醇化物中间体与硝基烯烃进行全碳[4+2]环化，从而以高产率和优异的对映选择性生成具有四个连续立构中心的手性环己烯。此外，非对映异构体的合成的产品是通过引入第二个空间控制的双功能催化剂实现的，4个异构体的16个可能的立体异构体的产品选择性地通过简单地使用两种催化剂和它们的（假）对映异构体。这些结果为羰基官能团的远程活化以及具有多个立体中心的复杂手性分子的立体分散合成提供了新的见解。
HOMO‐raising noncovalent activation of α‐aryl α,β‐unsaturated aldehydes using a bifunctional Brønsted base catalyst is achieved. The catalytically generated dienolate intermediate undergoes all‐carbon [4+2] cyclizations with nitroolefins, leading to chiral cyclohexenes with four contiguous stereocenters in high yields and with excellent enantioseletivity. Furthermore, the diastereodivergent synthesis of the products is realized by introducing a second steric control to the bifunctional catalyst; 4 isomers out of 16 possible stereoisomers of the products were selectively produced by simple use of two catalysts and their (pseudo)enantiomers. The results presented here provide new insights into the remote activation of the carbonyl functionality as well as the stereodivergent synthesis of complex chiral molecules with multiple stereocenters.