Selective Synthesis of cis-α,β-Unsaturated Sulfoxides and Sulfides by the Horner-Wittig Reaction with Bis(2,2,2-trifluoroethyl)phosphono Sulfoxides and Aromatic Aldehydes - Kokin, Keisuki; Tsuboi, Shuji; Motoyoshiya, Jiro; Hayashi, Sadao (Synthesis, 1996)