Question

Treatment of a cyclic ketone with diazomethane is a method for accomplishing a ring-expansion reaction.For example, treatment of cyclohexanone with diazomethane yields cycloheptanone. Propose a mechanism.

Short answer

Ring expansion is the reaction to expanding existing rings and forming compounds.

Diazo methane helps in expanding the ring by one unit.

Step-by-step solution

Ring-expansion reaction

Ring expansion is the reaction to expanding existing rings and forming compounds.

Diazo methane helps in expanding the ring by one unit.

Mechanism

The mechanism for the given reaction involves the following steps:

The carbanion of the diazo methane reacts with the carbonyl carbon and forms the respective product.

Mechanism of the reaction