A mild, selective and efficient Nazarov cyclization of divinyl ketones catalyzed by phosphomolybdic acid (PMA) is described. The process demonstrates a broad substrate scope with functional group tolerance under short reaction times. PMA supported on silicagel is more efficient than the bulk catalyst and is recycled up to three times without significant activity loss.
作者:Filippo De Simone、Julien Andrès、Riccardo Torosantucci、Jérôme Waser
DOI:10.1021/ol802970g
日期:2009.2.19
The first catalytic method for the cyclization of vinyl-cyclopropyl ketones (formal homo-Nazarov reaction) is reported. Starting from activated cyclopropanes, heterocyclic, and carbocyclic compounds were obtained under mild conditions using Bronsted acid catalysts. Preliminary investigation of the reaction mechanism indicated a stepwise process.