title: Metal-free Brønsted acid catalyzed formal [3 + 3] annulation. straightforward synthesis of dihydro-2H-chromenones, pyranones, and tetrahydroquinolinones.
abstract: Brønsted acids catalyze the addition of enolizable beta-diketones, beta-ketoesters, and vinylogous amides to alpha,beta-unsaturated aldehydes to lead to substituted chromenones, pyranones, and tetrahydroquinolinones in good yields under mild reaction conditions via a formal [3 + 3] cycloaddition.
authors: Sciences Chimiques de Rennes, Catalyse et Organométalliques, UMR 6226, CNRS-Université de Rennes 1, Campus de Beaulieu-35042 Rennes Cedex, France.
authors: Julie
authors: J
authors: Moreau
authors: Claudie
authors: C
authors: Hubert
authors: Jessika
authors: J
authors: Batany
authors: Loic
authors: L
authors: Toupet
authors: Thierry
authors: T
authors: Roisnel
authors: Jean-Pierre
authors: JP
authors: Hurvois
authors: Jean-Luc
authors: JL
authors: Renaud