The synthesis of ester and ketone analogues of 1-deoxynojirimycin and castanospermine

Abstract

1-Amino-1-deoxy-D-glucitol ( 3) was converted into the 3,4;5,6-di- O-isopropylidene protected ammonium salt 17 which was transformed further into the trans-fused piperidine acetonides 4–8 in six steps and 23–32% overall yield. In the final step, ring closure was effected via cleavage of the N-Boc group of intermediates 27–29 with trimethylsilyl iodide: this enabled internal, face selective 1,4-addition of the free amino group to the (5,6)-α,β-unsaturated carbonyl moiety. Further modification and (or) deprotection of compounds 4–8 afforded the piperidine and indolizidine imino sugars 9–12 and 14–15.