Direct transformations of ketones to gamma-unsaturated thiols via
The reaction of a series of ketones with dimsylsodium in dimethyl sulfoxide resulting in the formation of gamma-unsaturated thiols was studied experimentally. [2,3]-Sigmatropic rearrangements of beta-unsaturated sulfinyl carbanions are involved at the key step of those transformations. DFT computations at the B3LYP/6-31+G level indicated that such rearrangements, as well as some typical [2, 3]-sigmatropic rearrangements, e.g., thermal rearrangements of allyl sulfoxides and Wittig rearrangements of sulfur ylides and lithiated allyloxy methyl anions, are concerted and moderately synchronous processes. Negative (diatropic) nucleus-independent chemical shifts (NICS) and high diamagnetic susceptibility exaltations indicate that the transition structures of these [2,3]-sigmatropic migrations are aromatic.
Fokin
AA
Department of Organic Chemistry, Kiev Polytechnic Institute, 37 Pobeda Ave. 252056, Kiev, Ukraine, and Computational Chemistry Annex, University of Georgia, Athens, Georgia 30602-2525, USA.
Kushko
AO
Kirij
AV
Yurchenko
AG
Schleyer
PR