Study On The Cyclization Reaction Of 1, 4 And 1, 5-Alkynols

This thesis consists of two Parts. In the first part, the recent progress made in the synthetic studies on tetrahydrofuran (THF) and tetrahydropyran (THP) rings involving the intramolecular C-0 coupling is briefly reviewed. In the second part, our own efforts toward the synthesis of THF and THP are described. The results obtained are outlined as follows:(1) a one-pot synthesis of THF and THP rings was achieved employing the gold-catalyzed cyclization of the corresponding 1,4 and 1,5-alkynols, and Et3SiH-mediated reduction of ketals. (2) Tetrabutyl ammonium fluoride (TBAF) was found to catalyze the cyclization of 6-hydroxyhex-2-ynoate and 7-hydroxyh ept-2-ynoate effectively. Based on this finding, a new protocol was developed for the synthesis of THF and THP rings.