A short and efficient synthesis of 2R,3R,4R-3,4-dihydroxyproline, 1,4-dideoxy-1,4-imino-L-xylitol, 2R,3R,4R,5S-3,4,5-trihydroxypipecolic acid, and 1,5-dideoxy-1,5-imino-L-iditol

The syntheses of pyrrolidine alkaloids (-)-1 and (+)-3 were accomplished in 47% and 60% overall yield from 2-azido-2-deoxy-L-idonate 5, while piperidi ne alkaloids (-)-2 and (+)-4 were obtained in 51% acid 53% overall yield fr om the same starting material. Key step includes iodine promoted one-pot cy clization, and selective deprotection of isopropylidene and 9-phenylfluoren -9-yl (Pf) group.