The first stereoselective total synthesis of the natural cryptopyranmoscatone B1 has been accomplished from 3,4,6-tri-O-acetyl-d-glucal. In addition to the double cross-metathesis reaction, a tandem nucleophilic addition-diastereoselective reduction of an in situ generated oxocarbenium cation have been used as key steps to assemble the glycoside moiety of the target molecule.