Highly Enantio- and Diastereoselective Synthesis of 1,2,3-Trisubstituted Cyclopropanes from α,β-Unsaturated Amides and Stabilized Sulfur Ylides Catalyzed by a Chiral Copper(I) Complex
Highly Enantio- and Diastereoselective Synthesis of 1,2,3-Trisubstituted Cyclopropanes from α,β-Unsaturated Amides and Stabilized Sulfur Ylides Catalyzed by a Chiral Copper(I) Complex
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DOI：
10.1021/acscatal.1c02723
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发表时间：
2021-09-03
期刊：
影响因子：
12.9
通讯作者：
Shibasaki, Masakatsu
中科院分区：
文献类型：
--
作者：
Pagire, Santosh K.;Kumagai, Naoya;Shibasaki, Masakatsu
以α，β-不饱和羰基化合物为原料，通过Michael加成引发的环合反应立体选择性地制备1，2，3-取代环丙烷是有机合成中的一个重要挑战。在这里，以前难以捉摸的α，β-不饱和酰胺与稳定的硫叶立德的催化不对称环丙烷化反应已经利用手性铜(I)络合物有效地完成。该Lewis酸催化体系在温和的反应条件下有效地将多种缺电子烯烃转化为相应的1，2，3-三取代环丙烷，产率高到极好，对映体和非对映选择性都很高。由此得到的富含对映体的环丙烷酰胺可以很容易地多样化为有希望的合成中间体，如β-氨基环丙烷羧酸，7-氮杂多林助剂的简单回收而不影响环丙烷单元的光学纯度，这突出了这种催化方法的合成效率。
The stereoselective preparation of 1,2,3-substituted cyclopropanes from alpha,beta-unsaturated carbonyl compounds in the carboxylic acid oxidation state through Michael addition-initiated ring-closure reactions is a significant challenge in organic synthesis. Herein, the previously elusive catalytic asymmetric cyclopropanation of alpha,beta-unsaturated amides with stabilized sulfur ylides has been efficiently accomplished utilizing a chiral Cu(I) complex. This Lewis acid catalytic system effectively converts a wide range of electron-deficient alkenes into the corresponding 1,2,3-trisubstituted cyclopropanes under mild reaction conditions in good to excellent yields with both high to excellent enantio- and diastereoselectivities. The resulting enantiomerically enriched cyclopropane amides can be readily diversified into promising synthetic intermediates such as beta-aminocyclopropanecarboxylic acids with the facile recovery of the 7-azaindoline auxiliary without influencing the optical purity of the cyclopropane unit, which highlights the synthetic efficacy of this catalytic approach.