Stereochemistry of the Bucherer–Bergs and Strecker Reactions of 4- tert -Butylcyclohexanone

Abstract

The spirohydantoin (α-isomer) obtained from 4-tert-butylcyclohexanone by the Bucherer–Bergs reaction has been shown by n.m.r., u.v., and considerations of steric hindrance to have the tert-butyl group and 1′-nitrogen atom cis; the β isomer obtained via the Strecker reaction, or via modified Bucherer–Bergs reactions employing carbon disulfide or carbon oxysulfide, has these groups trans. The differing stereochemical courses of the various reactions can be explained by a detailed consideration of their mechanisms.