[4 + 2] Cycloaddition reactions catalyzed by a chiral oxazaborolidinium cation. Reaction rates and diastereo-, regio-, and enantioselectivity depend on whether both bonds are formed simultaneously.
The reaction rates and products in enantioselective Diels-Alder reactions with a range of dienophiles correlate with the expected degree of concertedness of bond formation in the transition state.
Department of Chemistry and Chemical Biology, Harvard University,12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Santanu
S
Mukherjee
E J
EJ
Corey