Asymmetric Synthesis of Cyclopropanes with a Monofluorinated Quaternary Stereocenter

Abstract

New chiral fluorinated reagents (<i>N</i>-(dibromofluoroacetyl)oxazolidinones) were easily synthesized and used in an asymmetric cyclopropanation process. The Michael initiated ring closure reaction provided chiral cyclopropanes bearing a fluorinated quaternary stereocenter. Various electron-deficient alkenes can be used to efficiently obtain chiral polysubtituted fluorinated cyclopropanes in good yields. Moderate to very good <i>cis</i>/<i>trans</i> ratios were obtained with a high level of diastereoselectivity for each isomer