[3,3]-Sigmatropic rearrangement versus carbene formation in gold-catalyzed transformations of alkynyl aryl sulfoxides: mechanistic studies and expanded reaction scope.

ABSTRACT: Gold-catalyzed intramolecular oxidation of terminal alkynes with an arenesulfinyl group as the tethered oxidant is a reaction of high impact in gold chemistry, as it introduced to the field the highly valued concept of gold carbene generation via alkyne oxidation. The proposed intermediacy of α-oxo gold carbenes in these reactions, however, has never been substantiated. Detailed experimental studies suggest that the involvement of such reactive intermediates in the formation of dihydrobenzothiepinones is highly unlikely. Instead, a [3,3]-sigmatropic rearrangement of the initial cyclization intermediate offers a reaction path that can readily explain the high reaction efficiency and the lack of sulfonium formation. With internal alkyne substrates, however, the generation of a gold carbene s

SUBMITTER: Lu B 

PROVIDER: S-EPMC3704346 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature