Study On Thermally Induced Free Carbene N-S/S-S Bond Insertion

Free carbene is well known for its high reactivity,low stability,and difficultly in selectivity controls.Advances on the studies of free carbene is limited in comparison with that of metal carbene.Our works focus on the thermally induced gem-functionalization of diazo compounds via a process involving free carbene intermediate,and this method provides an effective approach for the construction of chiral carbon center with two heteroatoms.1.The free carbene N-S bond insertion reaction.A metal-free gem-functionalization reaction of diazo compounds with N-sulfenylsuccinimides via a formal N-S bond insertion process has been reported.The transformation features mild reaction conditions,broad substrate scope and functional group tolerance,offering an efficient approach to sulfide synthesis in moderate to high yields.In addition,the mechanism studies indicate the formation of free carbene under thermal conditions followed by ylide generation,and then N-S bond cleavage and C-N bond formation occurred in sequence to give the sulfide products.2.The free carbene S-S bond insertion.A metal-free gem-functionalization reaction of diazo compounds with diphenyl disulfide via a formal S-S bond insertion process has been reported.This transformation has broad substrate scopes.The success of this type of reaction provides a new method for the synthesis of dithioketal compounds.