Planar Chiral PHANOLs as Organocatalystsfor the Diels-Alder Reaction via Double Hydrogen-Bondingto a Carbonyl Group
- 11 June 2003
- journal article
- letter
- Published by Georg Thieme Verlag KG in Synlett
- Vol. 2003 (8) , 1121-1124
- https://doi.org/10.1055/s-2003-39890
Abstract
Planar chiral PHANOLs have been shown to catalyze Diels-Alder reactions of a,b-unsaturated aldehydes and ketones with various dienes. Rate accelerations of up to ca. 30-fold were obtained using the electron deficient 4,12-dihydroxy-7,15-dinitro[2.2]paracyclophane as a catalyst. It is proposed that the carbonyl group of the dienophile is activated via a double hydrogen-bonding mode. Although the PHANOLs are inherently chiral, little or no asymmetric induction was observed when using enantiopure (R)-PHANOL.Keywords
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