Optical Resolution of 2- and 3-Hydroxyalkyltriphenylphosphonium Salts. Stereoselective Synthesis of Enantiomerically Pure (E)- and (Z)-Homoallylic Alcohols

Optically active 2- and 3-hydroxyalkyltriphenylphosphonium salts were prepared by the optical resolution of their 2,3-di-O-benzoyltartrates. The reaction of these salts with butyllithium afforded the corresponding ylides, which reacted with aldehydes to give optically active (E)-homoallylic alcohols in good yields. 3-Hydroxyalkyltriphenylphosphonium salts were converted into the corresponding diphenylphosphine oxides by the reaction with aq NaOH, which reacted with sodium hydride followed by the addition of benzaldehyde to afford optically active (Z)-homoallylic alcohols.