SYNTHESIS AND CONFORMATIONAL-ANALYSIS OF A NOVEL TYPE OF SPIN-LABELEDBICYCLONUCLEOSIDE BASED ON A TETRAHYDROFURANO[2,3-C]PYRROLIDINE SUGARSKELETON

Bicyclonucleosides bearing a N-hydroxyamino-3,N-5-(1,1-ethano)-beta-D- furanosyl sugar moiety (15-18) have been prepared by glycosidation of the corresponding bicyclosugars obtained via an intramolecular reverse Cope elimination. The configuration of the asymmetric carbon of the 1 ,1-ethano bridge is the most important factor directing the conformati on of the N-hydroxypyrrolidine ring and its invertomers ratio as shown by variable temperature H NMR experiments.