REGIOSELECTIVITY AND STEREOSELECTIVITY IN STANNYLCUPRATION AND SILYLCUPRATION OF ALKYNES AND ENYNES USING PROTON SOURCES

Stannylcupration of alkyne 6 was performed using different proton sour ces such as phenols, alcohols and water; results showed that the cupra te reagent was not affected during the reaction. In all cases tested i n presence of a proton source, the vinylstannane 10 corresponding to a trans addition was not produced, while the distal and proximal isomer s 8 and 9 resulting from a cis addition were obtained in good yield. T he 8/9 ratio was dependent on the reaction temperature, the acidity an d the number of equivalents of the proton source. This study was also extended to the stannylcupration of enynes and silylcupration of alkyn es and enynes.