The regiochemistry in reactions of heterosubstituted allylic carbanions (1) is highly controlled via allylic aluminum or boron “ate” complexes which direct both carbonyl compounds and reactive halides to the a-position with high regioselectivity. For example, carbonyl compounds react with the oxygen-(3), sulfur-(12), selenium-(20), and silicon-(25) substituted allylic carbanions at the a-position via the ate complexes. Although the ...