A simple route to (R)-(+)-4-t-butoxycyclopent-2-enone

Abstract

(–)-10-Mercaptoisoborneol undergoes conjugate addition to racemic 4-t-butoxycyclopent-2-enone in methanol in the presence of a catalytic amount of N,N,N′,N′-tetramethylethylenediamine to give a 1 : 1 mixture of the sulphide adducts, which with m-chloroperbenzoic acid in ether at – 70 °C is converted into a mixture of the corresponding sulphoxides; a single diastereoisomer of one of the sulphoxides is easily obtained by crystallization, and the diastereoisomer is converted by silica gel into (R)-(+)-4-t-butoxycyclopent-2-enone (1).