Water as a proton source in regio- and chemoselective stannylcupration of alkynes and enynes

Stannylcupration of silylated alkynes or enynes does not proceed under clas sic conditions, but in the presence of methanol as a proton source the sily l group was removed and stannylation takes place. In order to preserve the silylated alkyne function, stannylcuprations of methyl-substituted alkyne 5 or enynes 12 and 16 were carried out in a competitive reaction in the pres ence of water in the cuprate solution. High yields and total regio-, stereo - and chemoselectivity were observed and the silylated alkyne function was preserved under these conditions.