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.
Hawkins
Joel M
JM
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
Nambu
Mitch
M
Loren
Stefan
S