Rhodium‐Catalyzed Asymmetric Cycloisomerization and Parallel Kinetic Resolution of Racemic Oxabicycles. Issue 34 (15th July 2016) - Loh, Charles C. J.
Abstract: While desymmetrizations by intermolecular asymmetric ring‐opening reactions of oxabicyclic alkenes with various nucleophiles have been reported over the past two decades, the demonstration of an intramolecular variant is unknown. Reported herein is the first rhodium‐catalyzed asymmetric cycloisomerization of meso ‐oxabicyclic alkenes tethered to bridgehead nucleophiles, thus providing access to tricyclic scaffolds through a myriad of enantioselective C−O, C−N, and C−C bond formations. Moreover, we also demonstrate a unique parallel kinetic resolution, whereby racemic oxabicycles bearing two different bridgehead nucleophiles can be resolved enantioselectively. Abstract : The oxabicycle dance ! An unprecedented rhodium‐catalyzed cycloisomerization of meso ‐oxabicyclic alkenes bearing bis‐tethered nucleophiles is presented. A parallel kinetic resolution was also demonstrated, where racemic oxabicycles bearing two different tethered nucleophiles can be resolved enantioselectively to give two constitutional isomers by differential nucleophilic attack.