CYCLIC ENOL ETHER SYNTHESIS VIA ARENESULFONYL IODIDE ADDITIONS TO ALKYNOLS

The reaction of arenesulfonyl iodides with alkynols generally provides adducts in good yields. Treatment of these adducts with KN(SiMe(3))(2 ) gives enol ethers; cyclisation of the functionalised pentenol (5) re sults in formation of the Exo-alkylidene tetrahydrofuran (7), whereas the homologous hexenol (6) gives the dihydropyran (8). Attempts to cyc lise the hexenol (6) with potassium t-butoxide under the conditions re ported by Short and Ziegler generally gave the endocyclic ether (8). C opyright (C) 1996 Elsevier Science Ltd