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DOI: 10.1055/s-0028-1087316
Ytterbium-Catalyzed Enantioselective Diels-Alder Reaction
Contributor(s):Mark Lautens, Praew ThansandoteChiba University, Japan
Highly Enantioselective Diels-Alder Reactions of Danishefsky Type Dienes with Electron-Deficient Alkenes Catalyzed by Yb(III)-BINAMIDE Complexes
J. Am. Chem. Soc. 2008, 130: 12588-12589
Publication History
Publication Date:
20 November 2008 (online)
Key words
ytterbium - enantioselective Diels-Alder reaction - Danishefsky diene
Significance
A highly stereoselective Diels-Alder reaction with Danishefsky-type dienes and electron-deficient alkenes has been accomplished using an ytterbium-BINAMIDE catalytic complex. A variety of dienophile substituents are tolerated, although the reaction is sensitive to steric interactions between the dienophile substituent and the silyloxy portion of the diene. The cyclic enone can be converted into a nonaflate, which the authors have shown to be a competent substrate for a variety of palladium-catalyzed cross-coupling reactions.
Comment
The present report is noteworthy since catalytic enantioselective Diels-Alder reactions with Danishefsky-type dienes have previously been challenging due to the Lewis acid sensitivity of these substrates. The diastereoselectivity is exclusively exo, which complements Rawal’s Cr(III)-catalyzed Diels-Alder reactions of heteroatom-substituted dienes giving exclusively endo selectivity (Y. Huang, T. Iwama, V. H. Rawal J. Am. Chem. Soc. 2000, 122, 7843). The authors also state that (+)-nonlinear effects are seen between the asymmetric induction and the enantiomeric composition of BINAMIDE, suggesting that non-reactive aggregates might be present.