Reactions of thiocarbonyl compounds with electrophilic and nucleophilic carbenes as well as with their metal complexes

A variety of cyclic and acyclic products are reported for reactions of thiocarbonyl compounds with carbenes and their metal complexed derivatives. Electrophilic and nucleophilic carbenes react with non-enolizable thioketones yielding thiocarbonyl ylides or 1,3-zwitterions, respectively, as plausible, reactive intermediates. In most cases, the initially formed intermediates undergo 1,3-electrocyclization yielding respective thiiranes, which, depending on the substitution pattern, are either isolated as final products or extrude elemental sulfur forming substituted ethylene derivatives. In addition, reactive thiocarbonyl ylides formed from alpha-oxo substituted carbenoids after the thiophilic attack onto the C = S bond undergo competitive 1,3- versus 1,5-dipolar electrocyclization leading to thiiranes or 1,3-oxathioles, respectively. From the point of view of potential practical applications (coordination chemistry, organometallic chemistry, polymer chemistry), zwitterionic hetarylidene dithiocarboxylates accessible as stable 1:1 adducts from the reactions of nucleophilic heterocyclic carbenes (NHCs) with carbon disulfide are of great interest.