High Acceleration and Improved Diastereoselectivity of Intramolecular Ene-Type Reactions by Diethylaluminum Chloride

Article abstract of DOI:10.1002/hlca.19800630728

The pyrrolidines 2 and 10 were obtained by thermal ene-reactions at +70 deg and +180 deg from the (Z)-4-aza-1,6-diene 1 and from the (E)-4-aza-1,6-diene 9 in the ratios of 75:25 and 50:50, respectively.On the other hand, these cyclizations proceeded readily in the presence of diethylaluminum chloride at -78 deg and -35 deg giving in high yield the trans-pyrrolidine 2 from 1 with 100percent and from 9 with 89percent diastereoselectivity.