Indium-mediated allylation of aldehydes, ketones and sulfonimines with 2-(alkoxy)allyl bromides.

2-(Alkoxy)propenyl bromides are readily prepared from 1,3-dibromo-2-propanol in a two-step sequence involving hydroxyl protection and sodium hydride-induced dehydrobromination. Indium-mediated allylation of aldehydes, ketones, and sulfonimines with 2-(alkoxy)propenyl bromides furnishes the corresponding homoallylic alcohols and sulfonamines in good yields. The products can be easily transformed into β-hydroxy ketones and esters, as well as substituted dihydropyrans and protected β-amino acids. Chiral 2-(alkoxy)propenyl halides, derived from (-)-menthol and D-glucal, furnish diastereomerically enriched products.