Aspects of remote asymmetric induction using allylstannanes

Transmetallation of allylstannanes with heterosubstituents at the 4-, 5- and 6-positions using tin(IV) halides generates allyltin trihalides which react with aldehydes to give homoallylic alcohols with excellent 1,5-, 1,6- and 1,7-asymmetric induction. Preliminary investigations indicate that imines prepared from butyl glyoxalate react with the allyltin trichloride prepared from 4- and 5-benzyloxypent-2-enyl-tributylstannanes with useful 1,5-asymmetric induction.