80031-02-3

The invention belongs to the technical field of chiral compound recognition and purity determination, and particularly relates to an axial chiral biphenyl ring-chain isomeric compound, and a preparation method and an application thereof. The axial chiral

A copper-catalyzed Ullman reaction accompanied with oxidative C–N bond formation was used to access tricyclic heterocycles in a one-pot operation by using atmospheric air as the terminal oxidant. This modular synthesis approach was used to synthesize previously known and novel azole-containing heterocycles with different nitrogen position isomers. Fused heterocycles were further functionalized by palladium-catalyzed direct C–H arylation methodology. Various electron-rich and electron-poor functional groups were tolerated in the ortho, meta, and para positions of the aryl bromides.

Studies of substrates which offer an acidic hydrogen and an aryl bromide for reaction with an organolithium reagent have been carried out with a series of benzene bromo amides and bromo anilides as well as selected benzene bromo carboxylic acids, bromoanilines, and bromobenzylamines.A representative example is the reaction of N-ethyl-N-deutero-o-bromobenzamide (6-d) with 1-lithio-3-phenylpropane to give N-ethyl-o-deuterobenzamide (46percent, 94percent-d) (7-d), N-ethyl-o-bromobenzamide (6) (49percent), 3-deutero-1-phenylpropane (51percent, 92percent-d), and 1-bromo-3-phenylpropane (48percent).Product formation in this and related cases is explained by the operation of a two step sequence in which an initial deprotonation is followed by a bromine-lithium exchange which is accelerated with respect to mixing.Such a sequence is consistent with the results of deuterium labeling and with changes in product ratios on different mixing and with differently aggregated organolithium reagents.Support is provided for the operation of two pathways for the expedited bromine-lithium exchange reactions.In one pathway a high local concentration of the organolithium reagent promotes rapid reaction and in the second the exchange reaction occurs within an initially formed complex.The selectivity for removal of a bromine ortho to a lithiated carboxamide is found to be 5-8 with n-butyllithium, and satisfactory synthetic ortho selectivity is obtained for N-ethyl-2,5-dibromobenzamide with phenyllithium.

Reactions in which there is formal intramolecular transfer of an acidic deuterium to a site of halogen-lithium exchange could be interpreted to show that initial halogen-lithium exchange occurs faster than loss of the acidic deuterium.However studies of the competition between halogen-metal-deuterium exchange and deuterium loss for N-deuterio-N-alkyl-o, -m, and -p-halobenzimides are not consistent with that mechanism.We suggest an alternative in which initial loss of the acidic deuterium is followed by halogen-lithium exchange to give a dilithiated intermediate.Deuterium transfer to the site of halogen-lithium exchange then occurs by reaction of the dilithiated species intermolecularly with unreacted N-deuteriated amide.The halogen-lithium exchange is faster than complete mixing of the reactants and can occur either in an initially formed deprotonated complex or in a transient high local concentration of organolithium reagent.Evidence for both possibilities is provided.Two reactions from the literature in which halogen-lithium exchange appears to be faster than transfer of an acidic hydrogen have been reinvestigated and found to be interpretable in terms of similar sequences.