Efficient access to extended yagupolskii-umemoto-type reagents: Triflic acid catalyzed intramolecular cyclization of ortho- ethynylaryltrifluoromethylsulfanes

Abstract

(Figure Presented) King of the ring: S-(trifluoromethyl)benzo[b]thiophenium salts 1, as analogues of Yagupolskii-Umemoto type reagents, were synthesized by novel triflic acid catalyzed intramolecular cyclization of ortho- ethynylaryltrifluoromethylsulfanes 2. 1j is especially useful for the electrophilic trifluoromethylation of β-ketoesters and dicyanoalkylidenes. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.