Biomimetic polyene cyclizations - asymmetric induction in the cyclization of a chiral dienic imine

The acid-catalyzed cyclization of the chiral aldimine prepared from trans-5,9 dimethyldeca-5,9-dienal and (?)S-α-phenyl-ethylamine affords diastereoisomeric amino-5 dimethyl-2,9 octalines, the asymmetric induction being 65% in the trans-trans series and 35% in the cis-trans series.