A chiral acrylate equivalent for metal-free Diels-Alder reactions:: endo-2-acryloylisoborneol

The principle of metal-free activation of enones toward the Diels-Alder reaction with dienes is demonstrated by exploiting the capability of Brønsted acids to activate α′-hydroxyenones through hydrogen bonding. The diastereoselective application of such a principle is nicely realized by using a newly designed family of camphor-based chiral enones, which upon catalytic action of either trifluoroacetic or triflic acid lead to the corresponding cycloadducts with high chemical and stereochemical efficiency. Copyright © 2002 American Chemical Society.