Synthesis of perhydro-furo[2,3-b]pyran (and furan)-3-yl methanols by oxygenative radical cyclization

5-exo radical cyclization followed by oxygenation with molecular oxygen of various 3-halogeno-2-allyloxy-perhydro-pyrans and -furans gave the perhydro-furo[2,3-b]pyran (and furan)-3-yl methanols in one step. Two catalytic systems were efficiently used for this transformation : tributyltin hydride/AIBN/O-2 and Co(salen)/NaBH4/O-2. Yields were high and interesting selectivities were observed. The reaction is general and was successfully applied to carbohydrate derived substrates. (C) 1998 Elsevier Science Ltd. Ail rights reserved.