Stereoselective synthesis of both enantiomers of 1,4-anhydro-alditols, 1,4-anhydro-2-amino-alditols and D- and L-isonucleosides from 2,3-O-isopropylidene-D-glyceraldehyde using iodine-induced cyclization as the key step

We have stereoselectively prepared the enantiomeric 1,4-anhydro-alditols (- )-15 and (+)-15, 1,4-anhydro-2-amino-alditols (-)-19 and (+)-19, and isonuc leosides (-)-22, (+)-22 and 25, from 2,3-O-isopropylidene-D-glyceraldehyde. The key step was the iodine-induced cyclization of 4-pentene-1,2,3-triols 2 and 3 to give, respectively, the tetrahydrofuran derivatives 4 and 5. In these compounds we have optimized the substitution of iodine for oxygen-bea ring groups. Results were best when we used potassium superoxide as a nucle ophile. (C) 2001 Elsevier Science Ltd. All rights reserved.