SELECTIVE PROTECTION OF THE PRIMARY HYDROXYL-GROUPS OF OXETANOCIN-A AND CONFORMATIONAL-ANALYSIS OF O-PROTECTED OXETANOCIN-A

One of the two primary hydroxyl groups of oxetanocin A was protected s electively with acetyl and o-nitrobenzyl groups using enzymatic and ph otochemical reactions, respectively. On the basis of H-1-NMR spectrosc opy and NOE experiment, 4'-O-protected oxetanocin A was found to take syn conformation in an aprotic solvent irrespective of the kind of pro tecting group owing to an intramolecular hydrogen bond.