Allylation of Aldehydes Using Reuseable Polymer-Supported Sulfonamide

Significance

An allylation of aldehydes with allyltributyltin using a reusable polymer-supported sulfonamide was developed. Thus, the polymer-supported sulfonamide of glycine 4 was prepared in three steps from the beads of polystyrene. The beads of polystyrene 1 were treated with excess chlorosulfonic acid to give chlorosulfonylated polymer 2. Glycine ethyl ester was grafted onto 2 in the presence of Et₃N. Saponification of 3 with aqueous NaOH in MeOH followed by acidification with under hydrochloric acid gave the polymer-supported sulfonamide 4. Allylation of aldehydes 6 using 1.2 equivalents of 4 gave the corresponding homoallylic alcohols 7 in 84-99% yields. After this reaction, the generated polymer 5 was filtrated off and treated with hydrochloric acid to recover 4, which was still efficient after being reused at least five times.