 The Johnson – Corey – Chaykovsky reaction ( sometimes referred to as the Corey – Chaykovsky reaction or <unk> ) is a chemical reaction used in organic chemistry for the synthesis of epoxides , aziridines , and <unk> . It was discovered in 1961 by A. William Johnson and developed significantly by E. J. Corey and Michael Chaykovsky . The reaction involves addition of a sulfur ylide to a <unk> , aldehyde , <unk> , or <unk> to produce the corresponding 3 @-@ membered ring . The reaction is <unk> favoring trans substitution in the product regardless of the initial <unk> . The synthesis of epoxides via this method serves as an important <unk> alternative to the traditional <unk> reactions of <unk> . 
