Gold-Catalyzed Synthesis of Benzothio-phenes with Chirality Transfer

Significance

Reported is a gold-catalyzed chirality transfer reaction of optically active o-alkynyl­phenyl 1-arylethyl sulfides 1 to 2,3-disubstituted benzothiophenes 2. The present reaction proceeds with retention of configuration in the transfer of the 1-arylethyl stereocenter. Experiments with deuterium-labeled arylethyl sulfide suggest the involvement of an [1,3]-shift mechanism as shown. Compounds 1 are readily prepared by Mitsunobu reaction of commercially available (S)-1-phenylethanol with 2-bromobenzenethiol followed by Sonogashira coupling.