Tin-mediated regioselective acylation of unprotected sugars on solid phase

Methyl α-d-glucopyranoside, methyl α-d-mannopyranoside and methyl β-d-galactopyranoside bound on O-6 to a copolystyrene–DVB resin through a trityl ether linker, have been regioselectively acylated with benzoyl chloride after treatment with Bu2SnO and stannylene formation on solid phase. The benzoylation reactions proved to be highly regioselective affording 2-O benzoyl derivatives for glucose and 3-O benzoyl derivatives for galactose and mannose with high yield.