Tetraallylstannane and Weinreb amides: a simple ‘green’ route to N-protected homoallylic alcohols and allyl ketones

We have explored the addition of tetraallylstannane (7) to a variety of N-protected Weinreb amides (N-phthalimido and N-benzyl). Reactions were conducted in methanol and the ionic liquid, butylmethylimidazole tetrafluoroborate (bmim[BF4]), yields of the corresponding N-protected allylketones were moderate to good. Allylation of the corresponding aminoaldehydes gave excellent yields of homoallylic alcohols (68–94%) and moderate to good diastereoselectivities (50–86%).