Molecular Recognition of α,β-Unsaturated Carbonyl Compounds Using Aluminum Tris(2,6-diphenylphenoxide) (ATPH): Structural and Conformational Analysis of ATPH Complexes and Application to the Selective Vinylogous Aldol Reaction
journal contributionposted on 25.04.2003, 00:00 by Susumu Saito, Takashi Nagahara, Masahito Shiozawa, Masakazu Nakadai, Hisashi Yamamoto
Various α,β-unsaturated carbonyl compounds were coordinated with aluminum tris(2,6-diphenylphenoxide) (ATPH) to give the corresponding Lewis acid−base complexes in a distinctive coordination fashion (selective coordination). ATPH recognizes carbonyl substrates and subsequently orients itself as it forms a stable complex through selective coordination with the carbonyl oxygen. Selective coordination also confers a conformational preference to each carbonyl compound under the steric and electronic influence of ATPH, which enables the vinylogous aldol reaction of α,β-unsaturated carbonyl compounds to give the corresponding γ-aldol products with different regio- and stereoselectivities.