The Vinylogous Aldol Reaction of Unsaturated Esters and Enolizable Aldehydes Using the Novel Lewis Acid Aluminum Tris(2,6-di-2-naphthylphenoxide)
作者:Jeffrey A. Gazaille、Tarek Sammakia
DOI:10.1021/ol300738f
日期:2012.6.1
(ATNP), and its use in the vinylogous aldol reaction between methyl crotonate and enolizable aldehydes are described. ATNP is related to Yamamoto’s Lewis acid, aluminum tris(2,6-diphenylphenoxide) (ATPH), but the 2-naphthyl groups more effectively block the α-position of aldehydes, enabling the selective enolization of crotonateesters in the presence of enolizable aldehydes. Vinylogous aldol reactions
A highly enantioselective one-pot synthesis of homoallylic alcohols via tandem asymmetric allyl transfer/olefin cross metathesis
作者:Cheng-Hsia Angeline Lee、Teck-Peng Loh
DOI:10.1016/j.tetlet.2005.11.078
日期:2006.1
A highlyenantioselective one-pot synthesis of linear homoallylic alcohols with terminal ester functionality has been achieved. The reactions were controlled by ordered addition of reagents and catalysts, ensuring complete consumption of aldehyde. The synthetic utility of this strategy has been demonstrated in a short synthesis of a low boiling point intermediate for grahamimycin A.
Diastereoselective synthesis of protected syn 1,3-diols by base-catalyzed intramolecular conjugate addition of hemiacetal-derived alkoxide nucleophiles
作者:David A. Evans、Joelle A. Gauchet-Prunet
DOI:10.1021/jo00061a018
日期:1993.4
Reaction of the illustrated unsaturated hydroxy esters (X = OMe, R2 = H, Me) and amides (X = N(Me)OMe, R2 = H, Me) with benzaldehyde and potassium alkoxide or amide bases is reported. The resulting benzylidene acetals are obtained in good yields (71-84%) and with high selectivity (>90: 10). In addition to an exploration of the scope of the reaction, a mechanistic study, involving the use of deuterated benzaldehyde to ascertain the rate-determining step of the process, is described.