[reaction: see text] A allylation of aldehydes and imines (generated in situ from aldehydes and amines) with allyltributyltin promoted by recoverable and reusable the polymer-supported sulfonamide of N-glycine has been developed. Good to high yields were obtained in various cases. Most of the SnBu(3) residue can be recovered as Bu(3)SnCl. Highly stereoselective synthesis of N-Boc-(2S,3S)-3-hydroxy-2-phenylpiperidine 7 was achieved by using the P4a-mediated allylation of Boc-l-phenylglycinal as a key step.

A variety of carboxylic acids have been screened for mediating the allylation of aldehydes with allytributyltin in different solvents. A novel, general, and practical method of allylation of aldehydes promoted by carboxylic acids under mild reaction conditions has been developed. Among them, p-nitrobenzoic acid afforded high to quantitative yields of the homoallylic alcohol products, and can be easily recovered after workup by aqueous HCl. Glyoxylic acid self-catalyzed the allylation without adding any other promoter or catalyst to give the corresponding allylation product in good yield. The regioselectivity of the crotylation of aldehydes is tunable by controlling the acidity of the carboxylic acids. The crotylation of aldehydes produced the alpha-adduct as major products in moderate to good yields with CF(3)CO(2)H as a promoter. A possible mechanism for the allylation is also discussed.

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