The First Gold‐Catalyzed CS Bond Formation: Cycloisomerization of α‐Thioallenes to 2,5‐Dihydrothiophenes

One good ring deserves another: A highly efficient and stereoselective cycloisomerization of α-thioallenes to 2,5-dihydrothiophenes is the first example of a gold-catalyzed carbon–sulfur bond formation (see scheme, X=Cl, I). Both gold(I) and gold(III) salts can be used as the precatalyst, with AuCl and AuI giving the best yields. The method is of interest for the stereoselective synthesis of biologically active 2,5-disubstituted dihydro- or tetrahydrothiophenes. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2006/z503846_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.