Theoretical Study On The Mechanism Of Rhodium And Ruthenium-catalyzed Decarbonylation Addition Reaction

Transition metal-catalyzed decarbonylation addition is a hotspot in the field of metal organic synthesis chemistry in recent years.Through DFT?density functional theory?calculations,We studied the reaction mechanism of rhodium-catalyzed synthesis of aminoisocoumarin by C-H activation of isatoic anhydrides and alkynes and ruthenium-catalyzed synthesis of spirono-benzofuranone by C-H/C-C bond activation of 3-hydroxy-2-phenylchromone and alkyne respectively.Through the combination of data and image analysis,we determined the most likely reaction path and explained the phenomenon observed in the experiment reasonably by the calculated data.The research results of this paper are of great significance to the design of catalytic systems and substrates for such reactions and the related mechanisms.This paper includes the following two aspects of research:?1?Mechanism study of rhodium-catalysed decarbonylative annulation of isatoic anhydrides with alkynes through C-H bond activation for the synthesis of aminoisocoumarins.Various possible reaction paths of the reaction were studied by DFT calculation.By comparison,it was found that the reaction path proposed by the author,under the catalysis system of rhodium,in which isatoic anhydrides was activated by C-H bond and N-H protonation formed six-membered rhodiumacycle,was not reasonable.The most reasonable path is that the isatoic anhydrides first conducts N-H deprotonation to form an open-loop intermediate with isocyanate group,whose formation is crucial to the subsequent reaction path,and then generates the target product through C-H bond activation,alkyne insertion,reduction elimination and N-H protonation.?2?Mechanism study of ruthenium-catalyzed reaction of3-hydroxy-2-phenylchromones with alkynes through C-H/C-C bond activation to synthesis of spirobenzofuranones.The specific reaction path and the influence of the addition of PPh₃ligand on the reaction were studied by DFT calculation.It was found that the addition of PPh₃changed the speed step of the reaction and reduced the energy and activation energy of the whole reaction path.For asymmetric alkynes,combining the calculated data with the analysis of the key intermediate and the transition state structure,it is found that the main control factor of the regioselectivity is the steric hindrance effect.