Synthesis of phosphindoline oxides, tetrahydrophosphinoline oxides, and related compounds by cyclisation of allyl- and vinyl-phosphine oxides

Abstract

The acid-catalysed dehydration of β-hydroxyalkylphosphine oxides gives initially allyl- or vinyl-phosphine oxides, which cyclise to give five- or six-membered rings in which the alkyl chain forms a new carbon–carbon bond to either an aryl or another unsaturated alkyl chain. These reactions offer a general synthesis of the title compounds. A series of these compounds is described, including 4,5-dihydro-1,1,5,5-tetramethyl-3H-2a-phospha-acenaphthene 2a-oxide(18). Attempted 1,3-anionic cycloadditions of vinylphosphine oxide anions were not successful.