Reaction of secondary phosphine oxides with acylacetylenes

Abstract

Secondary phosphine oxides reacted with 1-alkanoyl-2-phenylacetylenes in chemoselective fashion under mild conditions (20°C, THF) in the absence of a catalyst (diphenylphosphine oxide) or in the presence of potassium hydroxide [bis(2-phenylethyl)phosphine oxide] to give 1-alkyl-1-diphenyl(or 2-phenylethyl)-phosphoryl-3-phenylprop-2-yn-1-ols in up to 96% yield. The reaction of diphenylphosphine oxide with 1-alkanoyl-2-phenylacetylenes in the system KOH-THF (20°C) afforded not only adducts at the carbonyl group but also products of double α,β-addition at the triple bond, 2,3-bis(diphenylphosphoryl)-3-phenylpropan-1-ones.