摘要:
Starting from 5'-O-trityl-2',3'-seco-uridine, reconstruction of a furanose structure was carried out by the following sequence of reactions: (I) regioselective introduction of a phenylselenenyl group to the 2'-position of the 2',3'-seco-uridine, (2) oxidation and subsequent Wittig reaction of the 3'-hydroxyl group and (3) intramolecular radical reaction (5-exo-trig ring closure) leading to 3'-C-carbon-substituted 2',3 '-dideoxyuridine. Also studied is the Pummerer reaction of the 2'-phenylseleno derivative of 2',3'-seco-uridine. The resulting product, an alpha-(acyloxy)phenylselenide, also serves as a substrate for the radical cyclization to allow the introduction of a hydroxyl group at the 2'-position of the reconstructed furanose ring. (C) 2001 Elsevier Science Ltd. All rights reserved.