Studies On The Gold-catalyzed Ring Opening Reaction

Both carbon-carbon bond formation and cleavage processes are important in organic synthesis. Carbon-carbon bond cleavage by a transition metal complex is of interest in its application to important industrial processes such as petroleum refining, alkane skeletal rearrangements, and cracking. Nowadays, most cases of carbon-carbon bond cleavages are ring fragmentations. Ring fragmentations are particularly useful because they result in newly ployfunctional groups' compounds. So, ring opening reactions are becoming more and more attractive in organic chemistry.This thesis is concerned with studies on the ring opening reaction catalyzed by gold catalysis via carbon-carbon bond cleavages. It is divided into three parts as follows:In chapter 1, a comprehension overview in the fields of homogeneous catalysis by gold is given and the basic principles are discussed. The oxidation reaction, the addition of nucleophiles to C-C multiple bonds, cyclization of enynes and cyclopropane compounds catalyzed by gold were intrduced.In chapter 2, we introduced a newly gold-catalyzed ring opening of 1-cyclopropyl-2-yn-ols with nucleophiles leading to (Z)-congjugated enynes.We have developed an efficient approach to (Z)-congjugated enynes. The reaction was proceeded under very mild conditions with a complete regio- and stereoselectivity.In chapter 3, general reaction of a-hydroxy epoxides were introduced. We have developed a newly gold-catalyzed ring opening reaction ofα-hydroxy epoxides containing carbon cycle. We have disclosed the rule of ring opening reaction. And the plausible mechanism was proposed.