A Study Based On The Cyclization/Carbonylation Reaction Of Mo（CO）₆ With Unsaturated Hydrocarbons

Transition metal-catalyzed carbonylation reactions are a class of reactions that introduce carbonyl groups within the molecules of organic compounds,which are usually carried out under mild conditions with high yields and high selectivity,and are one of the hot research topics in organic synthesis.Indolones and quinolones have special pharmacological and biochemical activities and are intermediates of many drugs and functional materials,and can also be applied in the synthesis of natural products.In this paper,Mo(CO)6 was used as the carbonyl source for the synthesis of 2-indole-3-acetates with N-(2-iodophenyl)-N-methylacrylamide and alcohol/phenol carbonylation;2-indolone-3-acetamides with N-(2-iodophenyl)-N-methylacrylamide and aniline carbonylation;and N-methyl-N-(2-(phenylethynyl)phenyl)methacrylamide to give quinolinones.The structures of the synthesized products were verified by NMR and mass spectrometry,and the reaction mechanism was tentatively proposed by the experimental results and combined with literature analysis.The obtained results are as follows.(1)The optimal conditions for the synthesis of 2-indolone-3-acetates were as follows:PdCl2 as catalyst,PPh3 as ligand,K2CO3 as base,MeCN as solvent and Ar as protective gas,and the reaction was carried out at 100℃ for 10 h.Twenty 2-indolone-3-acetates were synthesized with column separation yields of 51%-98%,and the reaction mechanisms of cyclization,insertion and esterification were initially proposed.(2)The optimal conditions for the synthesis of 2-indol-3-acetamides were as follows:PdCl2 as catalyst,PPh3 as ligand,K2CO3 as base,MeCN as solvent,and Ar as protective gas,and the reaction was carried out at 100℃ for 12 h.Six 2-indol-3-acetamides were synthesized with column separation yields of 28%-62%,and the reactions of cyclization,insertion and amidation were initially proposed The reaction mechanism of cyclization,insertion and amination was initially proposed.(3)The optimal conditions for the synthesis of quinolinone compounds are:PdCl2 is a palladium catalyst,Cu(MeCN)4PF6 is a copper catalyst,DPPF is a ligand,MeCN is used as a solvent,and Ar is used as a protective gas under the reaction conditions of 100℃ After 24 hours of reaction,25 aryl quinolinone compounds were synthesized.The column separation yield was 55%-92%.The reaction mechanism of cyclization and insertion was initially proposed.2-Indolone-3-acetates,2-indol-3-acetamide and quinolones have specific pharmacological and biochemical activities,and the present study provides a new synthetic method for the synthesis of these three classes of compounds.