Highly Enantio- and Diastereoselective Hetero-Diels-Alder Reactions Catalyzed by New Chiral Tridentate Chromium(III) Catalysts.
Even moderately nucleophilic dienes react with simple aldehydes in the presence of a new Cr(III) catalyst in a hetero-Diels-Alder reaction [Eq. (1)]. Tetrahydropyranyl products with up to three stereogenic centers are generated in near-perfect diastereoselectivities and with greater than 90 % ee (99 % ee for the example shown). TBAF=tetrabutylammonium fluoride; TBS=tert-butyldimethylsilyl; TES=triethylsilyl.
Dossetter
AG
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138 (USA).
Jamison
TF
Jacobsen
EN