Asymmetric Lewis acid-catalyzed Diels-Alder reactions of alpha,beta-unsaturated ketones and alpha,beta-unsaturated acid chlorides.
[reaction: see text] Conformational analysis, van der Waals attractions, and transition structure calculations are combined to design an asymmetric Lewis acid-catalyzed Diels-Alder reaction for simple acyclic alpha,beta-unsaturated ketones and alpha,beta-unsaturated acid chlorides, giving up to 83 and 92% ee, respectively. The two-point-binding chiral recognition mechanism, Lewis acid-Lewis base coordination with boron and a van der Waals attraction with the naphthyl group, uses the inherent enone unit of simple alpha,beta-unsaturated carbonyl compounds, ending the need for auxiliary oxygen binding sites on the dienophile.
Pfizer Global Research and Development, Groton, Connecticut 06340, and Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, USA. joel_m_hawkins@groton.pfizer.com
Joel M
JM
Hawkins
Mitch
M
Nambu
Stefan
S
Loren