Asymmetric aza-Diels-Alder reaction: Enantio- and diastereoselective reaction of imine mediated by Chiral Lewis acid

Article abstract of DOI:10.1016/S0040-4020(01)80532-9

An efficient asymmetric aza-Diels-Alder reaction using chiral boron mediator is developed. The key to its success is the use of the chiral boron complex prepared in situ from (R)- or (S)- binaphthol and B(OPh)₃. The enantiomeric reaction of prochiral imine affords products of up to 90% ee. The double asymmetric induction of chiral imine using α-benzylamine as a chiral auxiliary is achieved with almost complete diastereoselectivity for both aliphatic and aromatic aldimines. This method is applied to the efficient synthesis anabasine and coniine of piperidine alkaloides.