Introverted Brønsted acid cavitands for selective conjugate addition reactions.

Four new quinoxaline-spanned cavitands having a diester hydrogen phosphate group were successfully synthesised. These phosphorous derivatives were applied in Brønsted acid-assisted catalytic conjugate addition reactions. The results were ranked with the control of diphenyl hydrogen phosphate as well as among those four cavitands. The structure–activity relationship revealed that the catalyst centre surrounded by two trans-positioned quinoxalines significantly influences reaction profile and product distribution. This comparative study provides us an intellectual basis for future catalytic cavitand chemistry and artificial enzymatic catalysis. [ABSTRACT FROM AUTHOR]