Regio- and steroselective metal-mediated synthesis of polyfunctionalized

- Silyl- and stannylcupration of alkynes bearing N- or S-based functional
groups takes place in a regio- and stereoselective fashion and the resulting vinyl
metal species are easily quenched with a wide range of electrophiles, thereby
resulting in a flexible and general route to polysubstituted silylated or stannylated
olefins. For the replacement of the vinylic R3M framework in the allylic-type systems
Pd(0) catalysis is needed and through Stille-type (M=Sn) or Heck-type (M=Si)
reactions, the controlling factors on the regio- and stereochemistry of the synthesis
of di- and trisubstituted olefins are disclosed. Conversely displacement of the R3Si
group and functionalization with electrophiles at C-2 can be performed even in the
absence of catalysts when N or S atoms are directly bound to the C=C moiety as part
of enamino or vinylsulfide frameworks respectively