The Sc(OTf)3-catalyzed allylation reactions of aldehydes with tetraallyltin proceeded smoothly in micellar systems to afford the corresponding homoallylic alcohols in high yields. The reactions were successfully carried out in the presence of a small amount of a surfactant in water without using any organic solvents.
Tin- and indium-mediated allylation in aqueous media: application to unprotected carbohydrates
作者:Enoch Kim、Dana M. Gordon、Walther Schmid、George M. Whitesides
DOI:10.1021/jo00072a038
日期:1993.9
The convenient and efficient indium- and tin-mediated allylation method for extending the carbon chain of unprotected carbohydrates is illustrated by preparation of 4-6 and 9-10. Various 2-deoxyaldoses can be synthesized by the allylation of aldoses. Indium-mediated reactions between ethyl 2-(bromomethyl)acrylate and aldoses provide access to 2-keto-3-deoxyulosonic acids. These reactions are diastereoselective; the major product contains a threo relationship between the newly generated hydroxyl group and the C-2 hydroxyl group of the starting carbohydrate. Results obtained from reactions involving authentic organotin and organoindium reagents and from the corresponding heterogeneous reactions are similar.