The mechanism of metal–ammonia reduction of camphor

Abstract

The reduction of camphor by active metals in liquid ammonia occurs by an electronation–protonation mechanism. Evidence is presented which indicates that protonation of a non-planar anion radical is involved in one if not the only route in the absence of a large excess of metal. A dianion seems to be involved when a large excess of metal is present. The effects of metal cations and a proton source are discussed. The camphor analogue of pinacol has been isolated and characterised.