环丙烷化
卡宾
环丙烷
位阻效应
烷基
环加成
组合化学
功能群
化学
化学选择性
杂原子
有机化学
催化作用
戒指(化学)
聚合物
作者
Bethany M. DeMuynck,Lumin Zhang,Emma K. Ralph,David A. Nagib
出处
期刊:Chem
[Elsevier]
日期:2024-03-01
卷期号:10 (3): 1015-1027
标识
DOI:10.1016/j.chempr.2024.01.006
摘要
Summary
Cyclopropanes are ubiquitous in medicines, yet robust synthetic access to a wide range of sterically and electronically diverse analogs remains a challenge. To address the synthetic limitations of the most direct strategy, (2 + 1) cycloaddition, we sought to develop a variant that employs non-stabilized carbenes. We present herein an FeCl2-catalyzed cyclopropanation that uniquely employs aliphatic (enolizable) aldehydes as carbene precursors. A remarkably broad range of alkenes may be coupled with these non-stabilized, alkyl carbenes. This extensive scope enables the synthesis of novel classes of cyclopropanes bearing alkyl, benzyl, allyl, halide, and heteroatom substituents, as well as spirocyclic and fused bicycles. Over 40 examples illustrate the broad generality, efficiency, selectivity, functional group tolerance, and practical utility of this approach. Mechanistic insights, gathered from stereochemical probes and competition experiments, are included to reveal the applicability of this non-stabilized carbene route for novel cyclopropane synthesis.
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