Gallium-mediated allyl transfer from bulky homoallylic alcohol to aldehydes via retro-allylation:: Stereoselective synthesis of both erythro- and threo-homoallylic alcohols

Retro-allylation of bulky gallium homoallylic alkoxides occurs to generate (Z)- and (E)-crotylgallium reagents stereospecifically, starting from erythro- and threo-homoallylic alcohols, respectively. The (Z)- and (E)-crotylgallium reagents immediately reacted with aromatic aldehydes to afford the corresponding erythro- and threo-homoallylic alcohols, respectively.