Chiral relay effect: 4-substituted 1,3-benzoxazol-2-(3H)-ones as achiral templates for enantioselective Diels-Alder reactions.
[reaction: see text] A new strategy to control the enantioselectivity of Lewis acid catalyzed reactions has been investigated. The use of N-acryloyl-1,3-benzoxazol-2-(3H)-ones substituted at position 4 leads to the formation of diastereomeric complexes as a result of the presence of a chiral axis. The stereochemical outcome of the reaction is controlled by the chiral catalyst and by the chiral axis, leading to high enantioselectivity improvements and, in one case, to an inversion of enantioselectivity.
Quaranta
Laura
L
Department of Chemistry and Biochemistry, University of Bern, CH-3000 Bern 9, Switzerland.
Corminboeuf
Olivier
O
Renaud
Philippe
P