The carbonylation of alkanes 1 under radical-reaction conditions was examined by using ethynyl triflone A as the unimolecular chain-transfer (UMCT) reagent. Good to moderate yields of ethynylketones 2 were prepared by means of this three-component coupling reaction. Higher CO pressures as well as lower concentrations of triflone A improved the efficiency of the reaction over the direct addition, the
Zn-ProPhenol Catalyzed Enantioselective Mannich Reaction of 2<i>H</i>-Azirines with Alkynyl Ketones
作者:Barry M. Trost、Chuanle Zhu
DOI:10.1021/acs.orglett.0c03737
日期:2020.12.18
The enantioselective Mannich reaction of 2H-azirines with alkynyl ketones is achieved under Zn-ProPhenol catalysis, delivering various aziridines with vicinal tetrasubstituted stereocenters in high yields with excellent enantioselectivities. The bimetallic Zn-ProPhenol complexes activate both the nucleophile and the electrophile in the same chiral pocket. A unique intramolecular hydrogen bond is observed