Bamford-Stevens reaction

The Bamford-Stevens reaction is a chemical reaction

Chemical reaction

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. They are studied by chemists under a field of science called chemistry. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, often coming about...

 whereby treatment of tosylhydrazones with strong base gives alkene

Alkene

In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

s. 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-alkene

Alkene

In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

s, while protic solvent

Protic solvent

In chemistry a protic solvent is a solvent that has a hydrogen atom bound to an oxygen as in a hydroxyl group or a nitrogen as in an amine group. More generally, any molecular solvent which contains dissociable H⁺, such as hydrogen fluoride, is called a protic solvent. The molecules of...

 gives a mixture of E- and Z-alkenes.

The Bamford-Stevens reaction is a chemical reaction

Chemical reaction

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. They are studied by chemists under a field of science called chemistry. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, often coming about...

 whereby treatment of tosylhydrazones with strong base gives alkene

Alkene

In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

s. 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-alkene

Alkene

In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

s, while protic solvent

Protic solvent

In chemistry a protic solvent is a solvent that has a hydrogen atom bound to an oxygen as in a hydroxyl group or a nitrogen as in an amine group. More generally, any molecular solvent which contains dissociable H⁺, such as hydrogen fluoride, is called a protic solvent. The molecules of...

 gives a mixture of E- and Z-alkenes.

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

Shapiro reaction

The Shapiro reaction or tosylhydrazone decomposition is an organic reaction in which a ketone or aldehyde is converted to an alkene through an intermediate hydrazone in the presence of 2 equivalents of strong base. The reaction was discovered by Robert H. Shapiro in 1975...

.

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

Carbenium ion

A carbenium ion is a carbocation of the trivalent and classical type R₃C⁺. A carbonium ion is a carbocation of the penta- or tetracoordinated nonclassical type such as an ion of the type R₅C⁺. Carbonium ions appear as nonclassical carbocations such as...

5.
In aprotic solvents, the diazo compound 3 decomposes to the carbene 7.