Mild boronic acid catalyzed Nazarov cyclization of divinyl alcohols in tandem with Diels-Alder cycloaddition

Boronic acid catalysis (BAC) was applied to a sequential Nazarov cyclization of divinyl alcohols/Diels-Alder cycloadditions leading to the preparation of highly functionalized bicyclic compounds in a highly diastereoselective fashion. In these one-pot transformations, highly functionalized dienes were generated in situ through boronic acid catalyzed Nazarov cyclizations of divinyl alcohols and were subsequently trapped with different dienophiles such as maleic anhydride and phenylmaleimide. The tandem reactions proceed directly from divinyl alcohols under very mild reaction conditions using air-stable catalysts, and as such this methodology represents a greener alternative to existing methods employing strong Lewis and Bronsted acids. (C) 2012 Elsevier Ltd. All rights reserved.