Bamford-Stevens reaction

The Bamford-Stevens reaction is a chemical reaction whereby treatment of tosylhydrazones with strong base gives alkenes. It is named for the British chemist William Randall Bamford and the Scottish chemist Thomas Stevens Stevens (1900-2000). The usage of aprotic solvents gives predominantly Z-alkenes, while protic solvent gives a mixture of E- and Z-alkenes.



The treatment of tosylhydrazones with alkyl lithium reagents is called the Shapiro reaction.

Reaction mechanism
The first step of the Bamford-Stevens reaction is the formation of the diazo compound 3.



In protic solvents, the diazo compound 3 decomposes to the carbenium ion 5.

In aprotic solvents, the diazo compound 3 decomposes to the carbene 7.