Studies On The Transition Metal Catalyzed Cyclization And Addition Reaction Of Acetylenes

This thesis is concerned with studies on the cyclization and addition reaction of acetylenes catalyzed by transition metal. It is divided into three parts as fellows:In chapter 1, a comprehensive overview in the field of homogeneous catalysis by gold is given and the basic principles are discussed. The oxidation reaction, C-C bond formation, the addition of nucleophiles to C-C multiple bonds, cyclization of enynes and reactions with organoboron, organostannanes and organosilanes compounds by gold catalyzed were introduced, respectively.In chapter 2, we introduced transition metal catalyzed cyclization leading to highly substituted furans. The advantages and drawbacks of the gold-catalyzed synthesis of substituted furans were given. We have developed an efficient recyclable cyclization reaction of 2-(l-alkynyl)-2-alken-l-ones by a more economical approach using Bu₄N[AuCl₄] as a catalyst in ionic liquids to multiply substituted furans. The catalyst is air-stable, inexpensive and readily available. The system was recycled and reused for six runs without any significant loss of catalyst activity.In chapter 3, general synthetic methods of β-halovinyl sulfones were given. The addition reaction of sulfonyl chlorides with acetylenes in the presence of copper salt was described. The reaction proceeds in toluene in the presence of CuCl and Me₂S as the additive for the stereoselective synthesis of single (Z)-β-chlorovinyl sulfones in moderate to excellent yields. This approach complements the addition reaction of sulfonyl halides to acetylenes. Furthermore, we investigated the scope of our new protocol and proposed the plausible mechanism.