The first chiral triaminosulfonium salt, tris((S,S)-3,4-diphenylpyrrolidino)sulfonium difluorotriphenylstannate, catalyzes trifluoromethylation of benzaldehyde with (trifluoromethyl)trimethylsilane to give the corresponding optically active alcohol with 52% ee. (C) 1999 Elsevier Science Ltd. All rights reserved.