A new organocatalytic system was tested as a promoter for the asymmetric addition of Chan’s diene to aldehydes under solvent-free conditions. This new organocatalyst generated in situ by mixing 1-naphthyl-TADDOL derivative and Emim BF4 was able to give enantioenriched vinylogous aldols and hetero-Diels-Alder cycloadducts. A mechanistic investigation through the detection of nonlinear effects confirmed
An efficient asymmetric aldol reaction of Chan's diene promoted by chiral Ti(IV)–BINOL complex
作者:Annunziata Soriente、Margherita De Rosa、Marina Stanzione、Rosaria Villano、Arrigo Scettri
DOI:10.1016/s0957-4166(01)00150-1
日期:2001.4
1.3-Bis-(trimethylsilyloxy)-1-methoxy-buta-1,3-diene (Chan's diene) can be conveniently used in asymmetric aldol reaction with aromatic, heteroaromatic, alpha,beta -unsaturated and aliphatic aldehydes in the presence of catalytic amounts (2-8% mol) of chiral Ti(IV)/(R)-BINOL complex. (C) 2001 Elsevier Science Ltd. All rights reserved.
Candida Rugosa lipase-catalyzed kinetic resolution of β-hydroxy-β-arylpropionates and δ-hydroxy-δ-aryl-β-oxo-pentanoates
作者:Chengfu Xu、Chengye Yuan
DOI:10.1016/j.tet.2004.12.059
日期:2005.2
A simple and convenient method was reported for the preparation of optically active beta-hydroxy-beta-arylpropionates, delta-hydroxy-delta-aryl-beta-oxo-pentanoates and their butyryl derivatives via CRL-catalyzed hydrolysis. The optically active products are potential precursors of some chiral pharmaceuticals and natural products. (C) 2005 Elsevier Ltd. All rights reserved.
Solvent-free asymmetric vinylogous aldol reaction of Chan's diene with aromatic aldehydes catalyzed by hydrogen bonding
Chan's diene proved to react with aromatic aldehydes under organocatalytic conditions in presence of a chiral naphthyl-TADDOL derivative to give vinylogous aldols (up to 65% ee) with complete gamma-selectivity. A further process of hetero-Diels-Alder cycloaddition, leading to chiral pyran-4-one derivatives (up to 60% ee), was favoured by electron-withdrawing substituents on the aromatic ring. (C) 2009 Elsevier Ltd. All rights reserved.