Synfacts 2007(2): 0212-0212  
DOI: 10.1055/s-2006-955788
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart · New York

Direct Aza-Hetero-Diels-Alder Reaction

Contributor(s): Benjamin List, Sebastian Hoffmann
H. Liu, L.-F. Cun, A.-Q. Mi, Y.-Z. Jiang, L.-Z. Gong*
University of Science and Technology of China, Hefei, Chengdu Institute of Organic Chemistry, and Graduate School of Chinese Academy of Sciences, Beijing, P. R. of China
Further Information

Publication History

Publication Date:
23 January 2007 (online)

Significance

An enantioselective direct aza-­Diels-Alder reaction between cyclohexenone 1 and aromatic aldimines 2 is described. The formation of various aromatic substituted isoquinuclidines 3 is efficiently catalyzed by phosphoric acid 4, derived from H8-binol. Compounds 3 were obtained in high yields with good enantioselectivites and moderate diastereomeric ratios. Brønsted acid catalyst 4 activates both aldimines 2 and enone 1 by shifting the equilibrium towards the dienol. Importantly, no enamine-generating catalyst or second Brønsted acid was needed. Additionally, the authors described a one-pot, three-component reaction between cyclohexenone 1, aldehydes 5 and p-anisidine 6.