Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 107, Issue 48, Pages 20642-20647Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1001150107
Keywords
asymmetric synthesis; Michael reaction; organocatalysis
Categories
Funding
- Bologna University
- Catalan Institution for Research and Advanced Studies
- Institute of Chemical Research of Catalonia Foundation
- ICREA Funding Source: Custom
Ask authors/readers for more resources
In spite of the many catalytic methodologies available for the asymmetric functionalization of carbonyl compounds at their alpha and beta positions, little progress has been achieved in the enantioselective carbon-carbon bond formation gamma to a carbonyl group. Here, we show that primary amine catalysis provides an efficient way to address this synthetic issue, promoting vinylogous nucleophilicity upon selective activation of unmodified cyclic alpha,beta-unsaturated ketones. Specifically, we document the development of the unprecedented direct and vinylogous Michael addition of beta-substituted cyclohexenone derivatives to nitroalkenes proceeding under dienamine catalysis. Besides enforcing high levels of diastereo- and enantioselectivity, chiral primary amine catalysts derived from natural cinchona alkaloids ensure complete gamma-site selectivity: The resulting, highly functionalized vinylogous Michael adducts, having two stereocenters at the gamma and delta positions, are synthesized with very high fidelity. Finally, we describe the extension of the dienamine catalysis-induced vinylogous nucleophilicity to the asymmetric gamma-amination of cyclohexene carbaldehyde.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available