“Chelation” Vs “Steric” Controlled Stereoselective Simmons-Smith Cyclopropanation on Carbofuranose and Ketal Templates

Abstract

Herein we discuss the “Chelation” Vs “Steric” controlled off-template stereoselectivity in Simmons-Smith cyclopropanation reaction. Different carbofuranose templates with altered C3 and C4 stereocenters, have been used. Steric crowding of the protecting group of the primary hydroxyl groups was key to achieve stereospecific reaction. The protocol was then extended cyclic ketal moieties. This protocol can serve synthetic chemists as plethora of natural products contain cyclopropane fragments and C-methyl stereocenters, which can be achieved by a simple hydrogenation reaction.