Enantioselective Oxidative Multi-Functionalization of Terminal Alkynes with Nitrones and Alcohols for Expeditious Assembly of Chiral α-Alkoxy-β-amino-ketones
functionalization of alkynes has emerged as an effective method in synthetic chemistry in recent decades. However, enantioselective transformations via metal carbene intermediates are quite rare due to the lack of robust chiralcatalysts, especially in the intermolecular versions. Herein, we report the first asymmetric three-component reaction of commercially available alkynes with nitrones and alcohols, which affords
The first highlydiastereoselective and enantioselective catalytic formal [4 + 3] cycloaddition of 1,1-cyclobutane diester with nitrone has been developed. Sterically hindered chiral SaBOX/Cu(II) complex promotes the reaction efficiently with a broad substrate scope, producing a range of multifunctionalized optically active 1,2-oxazepanes with excellent stereocontrol (up to >99/1 dr and 97% ee).
gold and chiral phosphoric acid cooperatively catalyzed enantioselective oxidative cyclization/Mannich-type addition reaction of homopropargyl amides with nitrones has been developed, which provides chiral pyrrolidin-3-ones in high yields with excellent enantioselectivities under mild conditions. This reaction employed stable and readily available alkynes as non-diazo carbene precursors, which provides
Chiral tris(oxazoline)/Cu(I) complexes are demonstrated as a type of efficient catalysts for the asymmetric Kinugasa reaction of terminal alkynes with C-arylnitrones, providing a highly enantio- and diastereoselective access to optically active beta-lactams. (C) 2012 Elsevier Ltd. All rights reserved.