6-DEOXY-ALLO-NOJIRIMYCIN IN THE RACEMIC AND D-SERIES, 6-DEOXY-D,L-TALO-NOJIRIMYCIN, THEIR 1-DEOXYDERIVATIVES AND 6-DEOXY-2-D,L-ALLOSAMINE VIA HETERO-DIELS-ALDER CYCLOADDITIONS

Diels-Alder cycloaddition of hexadienal dimethylacetal 3 to achiral ac ylnitroso-dienophile 5a gave the racemic cycloadducts 7a-c and, to chi ral chloronitroso-dienophile 6, enantiomerically pure D-10a as sole ad duct. Simple chemical transformations led to 6-deoxy-2-D,L-allosamine 15b, to 6-deoxy-D,L and D-allo-nojirimycin 15a, D-15a, to 6-deoxy-D,L- talo-nojirimycin 15c as well as to their l-deoxy-derivatives 16a, D-16 a, 16c via their crystalline l-deoxy-l-sulfonic acid derivatives (sulf ite adducts). Amino-sugars 16a,c are mixtures of alpha- and -beta-anom ers and of the corresponding imines. (C) 1997 Elsevier Science Ltd.