Applications Of High Efficiency P,N-Ru(?)Catalytic System In The Hydrogen Auto-Transfer C-C Formation Reactions

The hydrogen auto-transfer C-C formation reaction has attracted significant interests in recent years due to their good atom-economy.Among the reported examples,organic ligands were usually employed to stabilize the transition metal complex catalysts.Thus the development on the structure of ligands is an important topic in the hydrogen auto-transfer C-C formation reactions.In addition,research on exploring the reacting mechanisms between the catalyst and the intermediates among the catalytic process is beneficial to the design of new catalysts with high effiency and better selectivity.In this thesis,we synthesized six P,N ligands based on 2-aminopyridine and 2-aminopyrimidine,and explored their catalytic activities in the Ru-catalyzed hydrogen auto-transfer C-C reactions.The works are mainly listed as follows:(1)The research of applying organic ligands into the transition-metal catalyzed hydrogen auto-transfer C-C reactions was reviewed.(2)Six P,N ligands based on 2-aminopyridine and 2-aminopyrimidine were synthesized and characterized.The catalytic performances of catalytic systems containing different ligands and Ru sources toward the hydrogen auto-transfer alkylation of ketones with primary alcohols were examined.By using the[RuCl2(?6-p-cymene)]2-PyNHPPh2 catalytic system,the aspects such as solvents,base,catalytic loading and reaction time were optimized.This catalytic system could be suitable for a diverse of substracts containing not only phenones,cyclic ketones and benzyl alcohols,but also the steric hindered alkyl ketones,hydroxymethyl heteroaryls and alkyl alcohols.(3)The mechanism study of in-situ monitoring the reaction by 1H NMR and ESI-MS revealed the existence of a stable cationic[Ru(?6-p-cymene)(?2-PyNHPPh2)H]+ ruthenium hydride intermediate since the strating of reaction.The observed organic intermediates were consistent with a three step reaction containing dehydrogenation,alkylation and hydrogenation.The final step where the ruthenium catalysed transfer hydrogenation reduction of ?,?-unsaturated ketone with benzyl alcohol may be performed separately verified the hydrogen auto-transfer ability of the Ru catalyst.