Novel and efficient method for the allylation of carbonyl compounds and imines using triallylaluminum

This is the first report of the use of triallylaluminum as a reagent for the allylation of carbonyl compounds and imines. The allylation of ketimines without additional metal catalyst is known so far only in the case of the Grignard reagent. Triallylaluminum is a useful alternative to provide the homoallylic amines in excellent yield upon addition to aldimines and ketimines. The significant reactivity of this reagent was confirmed by its reaction with a sterically rigid ketone such as adamantanone to provide 1-adamantyl-3-buten-1-ol in 98% yield. The chemoselectivity of triallyl-aluminum was demonstrated by using different ketoesters. It is noteworthy that triallylaluminum is prepared from allyl bromide and aluminum metal, and not from a Grignard reagent, and that the procedure is operationally simple, leading to good to excellent product yields.