Stereocontrolled 1,3-addition reaction of silyl ketene acetal to sugar nitrone: synthesis of d-gluco-homo-1-deoxynojirimycin and l-ido-homo-1-deoxynojirimycin

The 1,3-addition reaction of silyl ketene acetal 6 to d-glucose derived nitrone 7 followed by reductive cleavage of the N–O bond afforded d-gluco- and l-ido-β-amino ester derivatives of 9a and 9b. The diastereoselectivity in addition reaction was improved as well as altered by making use of different Lewis acids. Reduction of the ester group in 9a followed by hydrogenolysis gave amino alcohol 12a. Selective N-Cbz protection, hydrolysis and intramolecular reductive amination afforded d-gluco-homo-1-deoxynojirimycin 1d. Analogously, β-amino ester 9b was converted to l-ido-homo-1-deoxynojirimycin 1c.