6-deoxy-nojirimycin and 6-deoxy-gulo-nojirimycin in the racemic and D-series, D-fuco-nojirimycin and their 1-deoxyderivatives via hetero-Diels-Alder cycloadditions.

Nucleophilic ring opening of the cyclic sulfates (+/-)-9c and D-9c and of the epoxide (+/-)-13, or double substitution of the bis-triflate D-10 (derived from the Diels-Alder adduct of hexadienal dimethylacetal to achiral or enantiomerically pure nitroso-derivatives) led to 6-deoxy-nojirimycin and 6-deoxy-gulo-nojirimycin in the racemic and D-series, to D-fuco-nojirimycin and to their 1-deoxyderivatives via their crystalline 1-deoxy-1-sulfonic acid derivatives (sulfite adducts). 6-Deoxy-nojirimycin and its isomers are mixtures of alpha- and beta-anomers and of the corresponding imine. (C) 1997 Elsevier Science Ltd.