An Organocatalytic Asymmetric Tandem Reaction for the Construction of Bicyclic Skeletons

• Published in: Chemistry : a European journal Vol. 15; no. 42; pp. 11384 - 11389
• Main Authors: Cao, Chun-Li, Zhou, You-Yun, Zhou, Jian, Sun, Xiu-Li, Tang, Yong, Li, Yu-Xue, Li, Guang-Yu, Sun, Jie
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 26.10.2009; WILEY‐VCH Verlag; Wiley
• Subjects: bifunctional catalysts; Chemistry; Chemistry, Multidisciplinary; density functional calculations; ketones; organocatalysis; Physical Sciences; Science & Technology; tandem reactions; 4 STEREOCENTERS; CATALYSIS; DOMINO REACTIONS; ALPHA,BETA-UNSATURATED ALDEHYDES; MULTISUBSTITUTED CYCLOPENTANES; HENRY REACTION; ketones; organocatalysis; density functional calculations; MICHAEL-ALDOL REACTIONS; TRICYCLIC CARBON FRAMEWORKS; bifunctional catalysts; STEREOGENIC CENTERS; tandem reactions
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200900696

Cyclic ketones react with (E)‐2‐nitroallylic acetates in the presence of catalytic pyrrolidine‐thiourea, which affords bicyclic skeletons with four or five stereocenters in one single reaction with up to 98 % ee in moderate to high yields. The cooperative effects of both enamine and the Brønsted acid are found to be crucial for the high reactivity and enantioselectivity of this cascade reaction, which is demonstrated by both theoretical calculation and experimental data. Bicycling skeletons? A highly enantioselective organocatalytic tandem reaction of (E)‐2‐nitroallylic acetates with cyclic ketones has been developed, providing an easy access to bicyclic skeletons with four or five stereocenters in one single reaction (see scheme).