Abstract
A diammonium salt of chiral 1,1′-binaphthyl-2,2′-diamine (2a) and trifluoromethanesulfonimide (Tf2NH) shows excellent catalytic activity and enantioselectivity for the Diels-Alder reaction of α-acyloxyacroleins. For example, in the presence of 5 mol% of 2a and 9.5 mol% of Tf2NH, the Diels-Alder reaction of α- (cyclohexanecarbonyloxy)acrolein with cyclopentadiene proceeded in EtCN at -75 °C to give the adducts in 88% yield with 92% exo and 91 % ee. The electron-donating property of the acyl group of the α-acyloxyacroleins increases the enantioselectivity due to the formation of strong intramolecular hydrogen bonding of the acyl group with a proton of the ammonium group in the transition state. This catalyst can be easily prepared in situ by mixing the commercially available chiral diamine and Tf2NH.
Original language | English |
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Pages (from-to) | 2457-2465 |
Number of pages | 9 |
Journal | Advanced Synthesis and Catalysis |
Volume | 348 |
Issue number | 16-17 |
DOIs | |
Publication status | Published - Nov 1 2006 |
Externally published | Yes |
Keywords
- 1,1′-binaphthyl-2,2′- diamine
- Ammonium salts
- Cycloaddition
- Diels-Alder reaction
- α-acyloxyacrolein
ASJC Scopus subject areas
- Catalysis
- Organic Chemistry