Configuration of α-hydroxyimino-ketones

Abstract

Four syn- and anti-isomeric pairs of acyclic α-hydroxyimino-ketones are studied. Some methods for determining their respective configurations are discussed and an additional procedure is described based on their reaction with toluene-p-sulphonyl chloride in pyridine. anti-Isomers are shown to undergo a second-order Beckmann cleavage, yielding acylium ions, which react with starting material to give oxime esters, whilst syn-isomers form stable toluene-p-sulphonates.