THE SYNTHESIS OF ESTER AND KETONE ANALOGS OF 1-DEOXYNOJIRIMYCIN AND CASTANOSPERMINE

1-Amino-1-deoxy-D-glucitol (3) was converted into the 3,4;5,6-di-O-iso propylidene protected ammonium salt 17 which was transformed further i nto the trans-fused piperidine acetonides 4-8 in six steps and 23-32% overall yield. In the final step, ring closure was effected via cleava ge of the N-Boc group of intermediates 27-29 with trimethylsilyl iodid e: this enabled internal, face selective 1,4-addition of the free amin o group to the (5,6)-alpha,beta-unsaturated carbonyl moiety. Further m odification and (or) deprotection of compounds 4-8 afforded the piperi dine and indolizidine imino sugars 9-12 and 14-15. (C) 1997 Elsevier S cience Ltd.