Chemo-, regio-, and stereoselective addition of secondary phosphine sulfides to α,β-unsaturated aldehydes

Abstract

The potential of secondary phosphine sulfides as promising building blocks for fine organic synthesis is far from being exhausted. The base-catalyzed addition of secondary phosphine sulfides to acrylonitrile has been reported briefly, without experimental details, but the reaction products have not been isolated and characterized [1]. In the presence of base catalysts, dialkyl- and diarylphosphine sulfides react with aliphatic and aromatic aldehydes to form ( hydroxyorganyl)diorganylphosphine sulfides [2, 3]. With formaldehyde and chloral, this reaction requires no catalysis [2, 4]. Under conditions of phase-transfer catalysis, diphenylphosphine sulfide is alkylated (for example, with methyl iodide) with almost quantitative formation of methyldiphenylphosphine sulfide [5]. We used the example of previously unknown bis(2-phenylethyl)phosphine sulfide easily prepared from available bis(2-phenylethyl)phosphine [6] and elemental sulfur to show for the first time that secondary phosphine sulfides chemo-, regio, and stereoselectively add to , -unsaturated aldehydes Ia, Ib to give 1-[bis(2-phenylethyl)thiophosphoryl]-3-R-prop-2en-1-ols IIa and IIb.