Studies On The Rhodium-catalyzed C-h Bond Activation And Palladium-catalyzed Cross Coupling Reaction

The transition-metal-catalyzed reactions are simple, efficient and versatile routes to the formation of C-C and C-O bonds, which represents the key step in a wide range of preparative organic processes. This dissertation consisted of two parts. The first one is focused on rhodium-catalyzed C-H bond activation. The second is focused on the palladium-catalyzed cross-coupling reactions and their applications in organic synthesis.In part one rhodium-catalyzed C-H bond activation in recent years were simply reviewed. Next, three reactions were studied as follows: (1) A rhodium-catalyzed ortho-benzoxylation of sp2 C-H bond by carboxylic acids was described. The procedure enjoys high efficiency, good functional group compatibility. Importantly, no external oxidant was required for the transformation. (2) A rhodium-catalyzed addition of aryl and alkenyl boronic acids to phthalaldehyde followed by an intramolecular aldehydic C-H bond esterification is described. It represents a facile and practical methodology to access 3-aryl and alkenyl phthalides in moderate to good yields. The procedure tolerates a series of functional groups, such as trifluoromethoxyl, nitro, methoxyl, fluoro, chloro and vinyl groups. (3) An efficient rhodium-catalyzed dimerization of diaryl acetylenes was achieved. Which provides the 1,2,3-triaryl naphthalene derivatives in moderate to good yields.In part two two cross-coupling reactions catalyzed by palladium were studied as follows: (1) A palladium-catalyzed crosscoupling reaction of aryl trimethoxysiloxanes with terminal alkynes was described. It is notable that the electron-deficient terminal alkynes also worked well in the procedure, which represents a practical alternative for the Sonogashira reaction. (2) A palladium-catalyzed Mizoroki-Heck-type reaction of aryl trimethoxysilanes with olefin was successfully developed. A series of ArSi(OMe)3 and olefins, including electron-rich and deficient analogues worked well in the procedure, affording the arylation products in moderate to good yields.