Molybdenum‐Catalyzed Deoxygenative Cyclopropanation of 1,2‐Dicarbonyl or Monocarbonyl Compounds

作者：Liya Cao, Jian‐Nan Luo, Jiasheng Yao, De‐Ku Wang, Yuanqing Dong, Chao Zheng, Chun‐Xiang Zhuo · 发表于：Angewandte Chemie International Edition · 年份：2021 · DOI：10.1002/anie.202103429 · 被引用次数：57 · 研究领域：Cyclopropane Reaction Mechanisms、Catalytic Alkyne Reactions、Catalytic C–H Functionalization Methods

The transition-metal-catalyzed cyclopropanation of alkenes by the decomposition of diazo compounds is a powerful and straightforward strategy to produce cyclopropanes, but is tempered by the potentially explosive nature of diazo substrates. Herein we report the Mo-catalyzed regiospecific deoxygenative cyclopropanation of readily available and bench-stable 1,2-dicarbonyl compounds, in which one of the two carbonyl groups acts as a carbene equivalent upon deoxygenation and engages in the subsequent cyclopropanation process. The use of a commercially available Mo catalyst afforded an array of valuable cyclopropanes with exclusive regioselectivity in up to 90 % yield. The synthetic utility of this method was further demonstrated by gram-scale syntheses, late-stage functionalization, and the cyclopropanation of a simple monocarbonyl compound. Preliminary mechanistic studies suggest that phosphine (or silane) acts as both a mild reductant and a good oxygen acceptor that efficiently regenerates the catalytically active Mo catalyst through reduction of the Mo-oxo complexes.