Reductive Cyclization of Bromoenynamides with Alcohols as Hydride Source: Synthesis and Reactions of 2-Amidodienes
Source: Advanced Synthesis & Catalysis, Volume 354, Number 17, 26 November 2012 , pp. 3187-3194(8)
Abstract:<title type="main">Abstract</title> Under basic conditions in alcoholic solvents, bromoenynamides undergo palladium-catalyzed cyclization to cyclic 2-amidodienes in good to excellent yields. This process represents the first use of an alcohol as a hydride source in an alkyne carbopalladation/termination sequence, with the site selectivity of the reduction showing a strong dependence on the tethering ring size (5-8), and the nature of the alcohol and base. Reaction of the dienes with a range of dienophiles (including alkenes, alkynes and arynes) under various conditions gives bi- and tricyclic azacycles, which can be further oxidized to the aromatic azacycles.
Document Type: Communications
Affiliations: 1: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K. phone: (+44)-1865-285-037, Fax: (+44)-1865-285-002 2: Syngenta Ltd., Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, U.K.
Publication date: 2012-11-26