A formal carbene insertion into C(O)−S bonds to access α-quaternary pyridines was achieved via a rhodium(II)-catalyzed in situ formation of sulfonium ylides from pyridotriazoles and thioesters followed by acyl group...
Bifunctionalized sulfonium ylides, sulfonium acyl sulfonyl methylides, were directly and efficiently prepared from various acetylenic sulfones and aliphatic sulfoxides under heating conditions. The current method features short reaction time, low cost, readily available starting materials, convenient operation and purification, providing an efficient access to widely applied bifunctionalized sulfonium ylides.
AbstractThis Account discusses several new reaction methods developed in our group that utilize sulfur-mediated reactions through sulfonium salts and ylides, highlighting the interplay of rational design and serendipity. Our initial goal was to convert aliphatic C–H bonds into C–C bonds site-selectively, and without the use of transition-metal catalysts. While a proof-of-concept has been achieved, this target is far from being ideally realized. The unexpected discovery of an anti-Markovnikov rearrangement and subsequent studies on difunctionalization of alkynes were much more straightforward, and eventually led to the new possibility of asymmetric N–H insertion of sulfonium ylides through Brønsted acid catalysis.1 Introduction2 Allylic/Propargylic C–H Functionalization3 Anti-Markovnikov Rearrangement4 Difunctionalization of Alkynes5 Asymmetric N–H Insertion of Sulfonium Ylides6 Conclusion
The first catalyst-free cascade deprotonation/intramolecular aldol reaction of α-carbonyl sulfonium ylides with 2-mercaptoindole-3-carbaldehydes and 2-mercaptobenzaldehydes was developed. A series of thieno[2,3-b]indoles and benzothiophenes were smoothly obtained in high to excellent...