Rhodium Catalyzed Asymmetric Ring-Opening Reaction of Oxabenzonorbornadienes with Anhydride

Transition metal catalyzed asymmetric ring-opening reaction (ARO) of oxabenzonorbornadienes is a useful tool in the formation of carbon-carbon bond or carbon-heteroatom bond, which have attracted extensive study and received great achievements over the past decades. A series of efficient catalysts have been established and the high-level control of enantioselectivity for these reactions have been realized. A wide range of nucleophiles including carbon and heteroatom nucleophiles have been used in this reaction. Anhydride is a common acylation reagent and there has been no report about the ARO reaction of oxabenzonorbornadienes with anhydride, which can generate some useful chiral compounds. In this work, Rh-catalyzed ARO of oxabenzonorbornadienes with acetic anhydride and propionic anhydride have been developed. The developed protocol could result in ARO product in high yield (up to 94%) and excellent enantioselectivity (up to 95% ee).