An Intramolecular Organocatalytic Cyclopropanation Reaction

Abstract

Catalytic processes that form functionalized cyclic molecules represent a key transformation for synthetic organic chemistry. Recently, a number of organocatalytic processes have emerged that often provide excellent levels of both enantioand diastereocontrol for the synthesis of cyclic molecules. Our recent studies have identified the utility of ammonium ylides for carbon–carbon bond formation. Herein we describe the development of a new organocatalytic intramolecular cyclopropanation reaction that forms synthetically versatile [n.1.0]bicycloalkanes by using a nucleophilic tertiary amine catalyst. The synthesis of these bicycloalkanes is most commonly carried out by interor intramolecular metal-catalyzed carbene transfer of diazo compounds to electron-rich alkenes [Eq. (1)]. Other than these methods there are few general