TRI-N-BUTYLTIN CUPRATE AS A TOOL FOR THE PREPARATION OF STANNYL DERIVATIVES OF CARBOHYDRATES

Reaction of tri-n-butyltin cuprate with sterically hindered allybromid es 10(E) and 10(Z) derived from D-galactose led exclusively to S(N)2 p roducts - allyl tributystannyl sugars 11(E) and 11(Z) in good yield an d with retention of the configuration of the double bond. Reaction of 'Bu3SnCu' with less sterically hindered allyl derivatives 5a and 5b (d erived from D-glucose) gave a mixture of S(N)2 and S(N)2' products (6 and 7 respectively). Treatment of methyl 3,4-tri-O-benzyl-6-O-mesyl-al pha-D-glucopyranoside (13) with 'Bu3SnCu' afforded organotin 14, which was further converted into an open-chain unsaturated aldehyde 15 (in the presence of zinc chloride). Reaction of 'Bu3SnCu' with sugar aldeh ydes provided stannyl carbinols, while with alpha,beta-unsaturated sug ar aldehydes the 1,4-addition products are formed. (C) 1997 Elsevier S cience Ltd.