A series of 1,6- and 1,7-bis(acylsilanes) have been prepared using a strate
gy of substitution of dihalo derivatives with a synthetic equivalent of the
trialkylsilylcarbonyl anion. These bis(acylsilanes) could easily be conver
ted, under Lewis acid activation, into cis-beta-hydroxyacylsilanes or the c
orresponding alpha,beta-unsaturated derivatives, by means of a completely s
tereoselective intramolecular aldol reaction.