The Quantum Calculation Of Reactivity Of Suzuki And Heck Cross-Coupling Reactions

Suzuki and Heck cross-coupling reactions are the important methods which used for carbon-carbon bond formation in the field of organic chemistry,and they play a great role in the synthesis of complicated pharmaceutical molecules,as well as total synthesis of natural products.Therefore,related study of these two cross-coupling reactions is always the hot spot.A great achievements have been obtained in the work about Suzuki and Heck cross-coupling reactions is mainly focus on the expansion of the substrates used,research of new catalysts,reaction conditions,selection of reagents and environmentally friendly etc.for years.Meanwhile,so do the quantum computing about the Suzuki and Heck cross-coupling.Scientists confirm the mechanism of cross-coupling reactions by computer simulation,and offer a proposal to organic chemists in more effective and reasonable catalytic cycle.All this work estabalishes the theoretical foundation of the research level of Suzuki and Heck cross-coupling reactions.All calculations were performed with the Gaussian 98 software at the B3LYP/6-311 G*level,by means of Density Functional Theory(DFT),focus on optimizing structures of substrate molecular and research of thermodynamics about the whole reactions.The cross coupling reactions contain aryl chlorides and aryl arenediazonium tetrafluoroborate salts as substrates in Suzuki cross coupling,respectively,and aryl arenediazonium tetrafluoroborate salts as substrate in Heck cross coupling.All work in this paper can be divided into two parts.First of all,optimized the molecular structures by means of function Hatree-Fock at the HF/3-21G level preliminarily.After HF optimized,we obtained the micro-structure analysis data at he B3LYP/6-311 G*level by means of DFT further.Simultaneously,atomic charge distribution characteristics and molecular orbital energy were also obtained by means of Hatree-Fock at the HF/STO-3G.POP=(Regular,Bonding,CHelp)level.Thermodynamic work was carried out authoritatively based in the optimized structures,meanwhile,mechanism of the reaction also can be tested through not only in the atomic net charge which organic chemist always involved,but also the molecular orbital energy.Secondly,we had obtained the ?rH and ?rG data through frequency analysis calculations by means of DFT at the B3LYP/6-311G*level,and had done the reactivity in thermodynamic research.Study of Suzuki and Heck cross-coupling reactivity by means of DFT played an important role in guiding the experiments through calculations.Rich experiences and high reference value in other organic reactions were provided through the calculations in this paper in future.