Palladium-catalyzed C-C Coupling Reactions For Constructing Muti-aryl Compounds

Organometallic chemistry is the cornerstone of modern synthetic chemistry, transition metal catalyzed organic reactions provide an efficient, simple, and highly selective bond-formation mode for organic synthesis. Among them, the late transition metal palladium caused widespread concern owing its excellent catalytic performance, palladium catalyzed C-C couplings was the most directly, and commonly used precedure for the C-C bonds formation, meanwhile, Csp2-Csp2 coupling reaction was one of the most powerful method to construct biaryl compounds and π-conjugated systems. Palladium-catalyzed carbonylation reaction is also one of the most effective and efficient way to prepare kinds of carbonyl-containing componuds, such as aldehydes, ketones, acids, esters, and amides, many of them have been successfully used in the industrial production and making great benefit for humans. For a synthesis method, it’s value was assessed by the vitality. With the developlent of information technology, great concern was invested to organic semiconductor materials based on π-conjugated system. Herein, it was the common expectations for synthetic chemists and materials chemists to efficiently prepare various materials molecules using organic methodology.This thesis firstly described the achievements of organometallic chemistry. And specifically focused on the development status of palladium catalyzed Csp2-Csp2 couplings. Then based on them, through rationally design, we mainly complete the following works.1. The first palladium catalyzed ligand-free Suzuki coupling of thiophene bromides with aryl boric acids was discribed. With palladium acetate as catalyst, potassium carbonate as base, in DMF, the reaction proceed smoothly under ligand free conditions while only require 0.02 mol % catalyst. thiophene rings were highly efficient installed into π-conjugated systems and a series of aryl capped thiophene/bithiophene organic backbone molecules were prepared. 2. The first palladium catalyzed carbonylative multiple C-C bonds formation for constructing fluoren-9-one building blocks was discribed. Using aryl halides as the electrophiles, aryl boronic acid as the nucleophile, CO as carbon linker and carbonyl sources, various substituted fluoren-9-ones has been developed under CO atmosphere when treated in Pd(OAc)2/PCy3 catalyst system in the presence of cesium carbonate/pivalic acid. The reaction even can be extended to gram scale and good results were obtained. We investigate the reaction by NMR, GC, and insitu-IR experiments, and then propose the corresponding mechanism.3. The first palladium catalyzed three components bifunctional carbonylation reaction of aryl halides, aryl boronic acid/ester and CO was discribed. By fine-tuning the reaction conditions, a variety of ladder-type oligo-p-phenylene skeleton compounds were constructed in two routes, respectively. Up to seven aromatic rings π-conjugated extended system indenofluorenedione with potential applications were prepared.