Reaction of phenylphosphonous acid with carbonyl compounds

Abstract

Phenylphosphonous acid adds to the carbonyl carbon atom of a variety of aldehydes and ketones to give α-hydroxyphosphinic acids. With benzylideneacetone the acid (III) is obtained along with a neutral compound shown to be the oxaphospholen oxide (IV). In contrast, condensation of phenylphosphonous acid with benzylideneacetophenone leads to the known γ-keto-acid (VII) and the oxaphospholen oxide (VIII). The bisphosphinic acid (XII) is obtained from diethyl acetylenedicarboxylate, and from maleic anhydride two acids of as yet uncertain structure have been isolated.