Alkenes and Cycloalkanes from Tosylhydrazones: The Aprotic Bamford-Stevens Reaction and Camphor Tosylhydrazone

Abstract

In 1952 Bamford and Stevens discovered that ptoluenesulfonylhydrazones of many different types of ketones decomposed on heating in a base to form alkenes, and cycloalkanes by insertion. In addition to the alkene, molecular nitrogen and p-toluenesulfinate anion are produced. There are three major reaction types: the protic Bamford-Stevens reaction (base induced decomposition of tosylhydrazones in protic solvents), the aprotic Bamford-Stevens reaction (base induced decomposition of tosylhydrazone in aprotic solvents), and reactions of tosylhydrazones with alkyllithium reagents, called the Shapiro reaction. Our main interest is the aprotic reaction and we will give the protic and alkyllithium reac�tions little attention. All three are discussed together since all are base induced. Our main concern with the aprotic reaction is with camphor tosylhydrazone. Camphor tosylhydrazone decomposes to a mixture of camphene and tricyclene when heated in aprotic solvents with sodium methylate (NaOMe) or sodium hydride (NaH). Some aprotic solvents often used are diglyme, decalin, and N1Ndimethylformamide. We employed diglyme and triglyme with NaOMe and an "'unreported"' aprotic solvent, dimethyl sulfoxide (DMSO), with NaH. [From introductory section]