Efficient access to extended Yagupolskii-Umemoto-type reagents: triflic acid catalyzed intramolecular cyclization of ortho-ethynylaryltrifluoromethylsulfanes.

Efficient access to extended Yagupolskii-Umemoto-type reagents: triflic acid catalyzed intramolecular cyclization of ortho-ethynylaryltrifluoromethylsulfanes.