Clemmensen Reduction

Abstract

The reduction of carbonyl groups (in aldehydes and ketones) to methylene groups with zinc amalgam and hydrochloric acid is generally known as the Clemmensen reduction. This reaction has also been reported to perform in acetic acid with zinc and HCl. The Clemmensen reduction generally converts carbonyl group into methylene group, but some abnormal reactions have also been reported to occur. It has been reported that alcohol is not the intermediate of the Clemmensen reduction and carbonium is involved in this reduction. Addition of alcohol in presence of toluene is found to improve the yield.