"Boron Ylide" Enables Stereoselective Construction of gem-Diborylcyclopropanes
Tongchang Fang1,2, Peng Zhang1, Chao Liu1,3
1State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China.
Abstract:
The stereoselective cyclopropanation of olefins with "boron ylide" is disclosed for the first time, providing a modular strategy for the synthesis of stereospecific diboryl-functionalized cyclopropanes. The chiral gem-diborylcyclopropanes are synthesized with excellent enantioselectivity with the aid of a chiral auxiliary. Based on the powerful transformable ability of boryl group, those challenging multi-quaternary carbon centers in cyclopropane units have been facilely constructed with excellent stereoselectivity. Control experiments indicate that the boryl groups are necessary for both chemoselectivity and stereoselectivity control.
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