Palladium-Catalyzed Carbothiolation of Alkenes and Alkynes for the Synthesis of Heterocycles

The
intramolecular carbothiolation of unsaturated hydrocarbons
using a palladium–NHC catalyst (NHC = N-heterocyclic
carbene) is described. Herein, a single catalyst system enables both
initial activation of a C­(sp2)–S bond through oxidative
addition and formation of a C­(sp3)–S bond through
a terminal reductive elimination, unlocking a completely atom-economical
transfer across alkenes. The reaction tolerates a variety of different
functional groups, exhibits excellent chemoselectivity in the presence
of competing thioether moieties, and can be applied to various alkenes
and alkynes. Furthermore, product derivatization was demonstrated
to access a broad variety of sulfur-containing compounds.