Nucleophilic Carbenes Derived from Dichloromethane
作者:Mingxin Liu、Nguyen Le、Christopher Uyeda
DOI:10.1002/anie.202308913
日期:2023.10.16
Nickel catalysts promote cyclopropanation reactions of electron-deficient alkenesusing dichloromethane as a methylene source. An asymmetric variant using a chiral pyridine-bis(oxazoline) ligand provides access to pharmaceutically relevant 2-aryl cyclopropyl carboxylates in highly enantioenriched form. The proposed mechanism involves the formation of a nucleophilic nickel carbene that reacts by a
Synthesis of Linear and Angular Triquinane Skeletons by <i>O</i>-Stannyl Ketyl-Promoted Fragmentation−Cyclization Reactions of α-Keto Cyclopropanes
作者:Eric J. Enholm、Zhaozhong J. Jia
DOI:10.1021/jo961655e
日期:1997.1.1
alpha-ketocyclopropane via O-stannylketyls. A preference for cleavage of the cyclopropane bond with the best orbital overlap with the ketyl radical sp(2)-orbital even in the presence of radical stabilizing groups is indicated by these results. An O-stannylketyl ring scission-cyclization resulted in the novel synthesis of either a linear or an angulartriquinaneskeleton depending on the length and