Optically Active Phosphine Oxides. 6.1conjugate Addition of Thiols and Alcohols to (-)-(S)-Methyl-Phenylvinylphosphine Oxide

Aliphatic and aromatic thiols have been added to a homochiral methylphenylvinylphosphine oxide, (-)-1, to provide the first examples of optically active β-alkylthioethyl and β-arylthioethyl phosphine oxides. The additions have typically required catalysis by base although in case of arylthiols they could have been performed thermally. Base catalyzed addition of alcohols to (-)-1 have analogously afforded optically active (β-alkoxyethyl)methylphenylphosphine oxides. Exemplary phenylsilane reduction of (-)-(β-ethylthioethyl)-methylphenylphosphine oxide to (-)-(β-ethylthioethyl)methylphenylphosphine demonstrates the faculty of transformation of the synthesized adducts into optically active phosphines bearing thioether functions.