Rhodium-catalyzed asymmetric ring opening reactions of oxabicyclic alkenes: catalyst and substrate studies leading to a mechanistic working model.
Catalyst and substrate studies have been performed on the rhodium-catalyzed asymmetric ring opening reaction. A working model is advanced that involves oxidative insertion with retention to form an organorhodium intermediate that then undergoes nucleophilic attack with inversion. Kinetic and competition experiments have uncovered evidence for a proton transfer step in the catalytic cycle that may activate both the allylrhodium intermediate and the nucleophile. We have also conducted experiments designed to understand which properties of the PPF-P(t)Bu(2) ligand contribute to the high reactivities and enantioselectivities.
Lautens
Mark
M
Davenport Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, Canada M5S 3H6. mlautens@alchemy.chem.utoronto.ca
Fagnou
Keith
K