Hutson GE, Türkmen YE, Rawal VH * The University of Chicago, USA
Salen Promoted Enantioselective Nazarov Cyclizations of Activated and Unactivated
Dienones.
J. Am. Chem. Soc. 2013;
135: 4988-4991
Key words
chromium - salen - Nazarov cyclization - dienones
Significance
Rawal and co-workers describe the highly enantioselective Cr/salen-catalyzed Nazarov
cyclization of both activated and unactivated dienones, giving the desired hydrindenone
products with three contiguous chiral centers in moderate to good yields and stereoselectivities.
Comment
This paper represents the first example of highly enantioselective Nazarov reactions
of unactivated dienones. A one-point activation mode was proposed and a counter-clockwise
conrotatory cyclization would release the R group into a less sterically congested
environment.
