Concise synthesis of five-membered ring carbasugars based on key ring-closing metathesis

A simple and efficient approach to the synthesis of five-membered ring carbasugars is achieved starting from readily available (R)-2,3-O-isopropylideneglyceraldehyde (2) through key ring-closing metathesis (RCM) in high overall yield. We have also confirmed its viability by preparing the core bicyclo [3.1.0] hexane framework presented in the potent antiviral nucleoside N-MCT 1.