HIGH-PRESSURE DIELS-ALDER REACTIONS OF 1-VINYL-2,2,6-TRIMETHYLCYCLOHEXENE CATALYZED BY CHIRAL LEWIS-ACIDS - AN ENANTIOSELECTIVE ROUTE TO A DRIMANE SESQUITERPENE PRECURSOR
J. Knol et al., HIGH-PRESSURE DIELS-ALDER REACTIONS OF 1-VINYL-2,2,6-TRIMETHYLCYCLOHEXENE CATALYZED BY CHIRAL LEWIS-ACIDS - AN ENANTIOSELECTIVE ROUTE TO A DRIMANE SESQUITERPENE PRECURSOR, Tetrahedron : asymmetry, 6(5), 1995, pp. 1069-1072
The Diels Alder reaction of 1-vinyl-2,2,6-trimethylcyclohexene 4 and 3
-(methoxycarbonyl)propenoyl)-1,3-oxazolidin-2-one 5 under high pressur
e, catalyzed by a chiral bis-imine copper(II) complex, yields a driman
e sesquiterpene precursor in a highly regio- and diastereoselective ma
nner with enantioselectivities up to 64%; nearly enantiomerically pure
material is obtained by one simple crystallization.