Theoretical Study On Cu/Ni Axial Chiral Complexes Catalyzed Several C-Coupling Reactions

Organometallic chemistry has important applications in the field of synthetic chemistry.Transition metals catalyzed coupling reactions by is one of the important topics in organic chemistry.Direct construction of biaryl compounds by C-H bond activation and construction y-lactam and its derivatives using unactive alkenes are two important types of reactions.Exploring the micro mechanism of the reaction by quantum chemical method and clarifying the origin of stereoselectivity,regioselectivity and substituent effect play an important guiding role in relevant experimental design.In this paper,the above two kinds of coupling reactions catalyzed by copper and nickel transition metals are deeply and systematically studied.1.C-H arylation of aromatics catalyzed by transition metalsWe studied the reaction mechanism of copper catalyzed synthesis of axially chiral biaryl compounds from azonaphthalene and arylboric acid.It is found that the essence of the reaction is the activation of C(sp2)-H bond controlled by non-covalent interaction.The reaction undergoes five sequential steps:(1)the transmetalation occurs via the-Naph group migration from B to Cu to form the naphthalenecopper species,(2)centrally chiral intermediate is formed via nucleophilic addition between naphthalenecopper species and azonaphthalenes,(3)The protonation process of the centrally chiral intermediate proceeds to obtain the Michael addition product with the aid of H2CO3,(4)the proton abstract process is completed with the aid of HCO3-,(5)the second protonation is achieved with the help of H2CO3 to obtain the final product.The nucleophilic addition is identified as the atroposelectivity-,and regioselectivity-determining step.Through the analysis of NCIs,it is found that the π-π interaction between the azonaphthalene substrate and the BINOL-derived phosphoramidite chiral ligand is indicated to play a substantial role for the control of the atroposelectivity.The more negative charge on N atom in azonaphthalene is the main reason leading to the selectivity of reaction region.The research results were published in the Molecular Catalysis(Mol.Catal.2021,515,111833).2.Asymmetric dicarbofunctionalization of alkenes catalyzed by transition metalsWe have studied the microcosmic mechanism of the cross-coupling reaction between unactive alkenes and arylboric acid catalyzed by nickel to form γ-lactam.Density functional theory calculation shows that the path with the lowest energy consists of six primitive steps:(1)ligand exchange between active catalyst and substrate,(2)zero valent nickel forms divalent nickel through oxidation addition of C-F bond,(3)the alkene migration insertion into Ni-C(=O)bond to form y-lactam Ni intermediate,(4)γ-lactam Ni intermediate undergoes the transmetalation with boronic acid,(5)the transmetalation occurs via the-Ph group migration,(6)the C-C reduction elimination of the aryl group with y-lactam results in cross coupling products.We found that the migration insertion of alkenes is important in determining stereoselectivity.The enantioselectivity originates from the CH…π interaction between the substrate and the axially chiral diphosphine ligand;it was found that β-H reductive elimination occurs when monosubstituted alkenes are used as substrates,which is consistent with the absence of the target product observed experimentally.The research results have been compiled into research paper and is currently being submitted.