Lewis Acid-Promoted Oxidative Cleavage of Carbon-Carbon Bonds: Synthesis of N-Arylated Lactam-Type Iminosugars

In this paper, a mild strategy for the oxidative cleavage of carbon-carbon bonds catalyzed by Lewis acid was developed in air condition at room temperature. Under such conditions, the bis-carbonyl compounds 3 were directly afforded from the reaction of D-ribose tosylate 1 and aniline in excellent yields through the oxidative cleavage of the key intermediate iminium-ion A and its tautomer enamine B. A series of N-arylated lactam-type iminosugars 5 were then successfully obtained by removing the isopropylidene group from 3 with the aid of the condensation agent DCC. Additionally, reduction of A and the removal of the isopropylidene group could provide N-arylated iminosugars 4. This strategy enables the oxidative cleavage of carbon-carbon bonds under mild conditions and facilitates the synthesis of the novel iminosugars with potent biological activity.