REGIOSELECTIVE AND STEREOSELECTIVE METAL-MEDIATED SYNTHESIS OF POLYFUNCTIONALIZED ALKENES

Silyl- and stannylcupration of alkynes bearing N- or S-based functiona l groups takes place in a regio- and stereoselective fashion and the r esulting vinyl metal species are easily quenched with a wide range of electrophiles, thereby resulting in a flexible and general route to po lysubstituted silylated or stannylated olefins. For the replacement of the vinylic R(3)M framework in the allylic-type systems Pd(0) catalys is is needed and through Stille-type (M=Sn) or Heck-type (M=Si) reacti ons, the controlling factors on the regio- and stereochemistry of the synthesis of di- and trisubstituted olefins are disclosed, Conversely displacement of the R(3)Si group and functionalization with electrophi les 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 vi nylsulfide frameworks respectively.