Complex and application of monophosphine monoazacyclo-carben nickel containing tricyclic hexyl phosphine

Abstract

The invention discloses a complex and application of monophosphine monoazacyclo-carben nickel containing tricyclic hexyl phosphine. The molecular formula of the complex of the monophosphine monoazacyclo-carben nickel is (PCy3)Ni[(RNCHCHNR)C]X2; in the molecular formula, the PCy3 is tricyclic hexyl phosphine; the R is tertiary butyl, 2,6-diisopropyl phenyl or mesitylene; the X is chlorine or bromine. The complex of monophosphine monoazacyclo-carben nickel containing tricyclic hexyl phosphine is simple to prepare, easy to operate, easy in purification of products and high in yield, can stably exist in air, and can efficiently catalyze cross coupling reaction of aryl methyl ether and aryl Grignard reagent.

Description

technical field [0001] The present invention relates to a nitrogen heterocyclic carbene nickel (II) complex, in particular to a monophosphine monoazacyclic carbene nickel (II) complex containing tricyclohexylphosphine and its reaction between aryl Grignard reagent and aryl methyl Applications in cross-coupling reactions between ethers. Background technique [0002] Biaryl compounds widely exist in natural products and pharmaceutical molecules, and are also industrially important fine chemicals, pharmaceutical intermediates, fluorescent whitening agents and agricultural chemicals. In recent years, with the deepening of people's understanding of the sustainable development of the chemical industry and the enhancement of environmental awareness, transition metal-catalyzed crossover between phenolic derivatives and aryl Grignard reagents through the activation of carbon-oxygen bonds Coupling reactions have received increasing attention and are becoming an important method for t...

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Problems solved by technology

[0004] In 2004, the Dankwardt research group found that a class of bis(tricyclohexylphosphine) nickel(II) complexes can effectively catalyze the cross-coupling reaction of aryl ethers and aryl Grignard reagents. The optimal conditions for this reaction are: 2-naphthalene The molar ratio of methyl ether and phenylmagnesium bromide is 1:3, the amount of catalyst is 2.5 mol%, add 5 mol% of tricyclohexylphosphine, react in the mixed solvent of methyl tert-amyl ether and ether for 15 hours, The temperature is 23°C, and the yield of cross-coupling products can reach 89% (see: Dankwardt, J. W. Angew. Chem. Int. Ed., 2004, 43, 2428); however, this reaction system also has some shortcomings, as shown A relatively large amount of Grignard reagent is required, and additional phosphine ligands need to be added, etc.

[0005] In 2011, Wang Zhongxia's research group designed and synthesized a new class of phosphine ligands containing heterocyclic skeletons, and synthesized the corresponding bisphosphine nickel (II) complexes, and found that they can catalyze the reaction between arylmethyl ether and aryl Grignard reagents. Cross-coupling reaction, this reaction optimal condition is: the mol ratio of 2-naphthyl methyl ether and p-methylphenylmagnesium bromide is 1: 1.5, and catalyst consumption is 2.5 mol%, reacts 24 hours in tetrahydrofuran solvent, temperature At 25°C, the yield of cross-coupling products can reach 92% (see: Xie, L.-G.; Wang, Z.-X. Chem. Eur. J., 2011, 17, 4972.); however, There are also some problems in this reaction system, such as the complex structure of the phosphine ligand used, cumbersome preparation steps, and part of the cross-coupling reaction can only be carried out at 120 °C.

[0007] In 2006, Matsubara's research group passed the bisphosphine nickel (II) complex (PPh 3 ) 2 NiX 2 The first case of triphenylphosphine-containing monophosphine nitrogen heterocyclic carbene nickel (II) complex (PPh 3 )Ni[(RNCHCHNR)C]X 2 (PPh 3 is triphenylphosphine, R is 2,6-diisopropylphenyl, X is chlorine or bromine) (see: Matsubara, K.; Ueno, K.; Shibata, Y. Organometallics, 2006, 25, 3422) , but when they tried to expand this kind of mixed-type nickel(II) complexes through this reaction using other nitrogen heterocyclic carbene ligands, they were unsuccessful, and could only obtain bis(azacyclic carbene) nickel(II) complexes. ) complexes

[0008] Therefore, there have been no reports of monophosphine mononitroheterocyclic carbene nickel (II) complexes containing other phosphine ligands or other nitrogen heterocyclic carbene ligands, let alone such mixed-type nickel (II) complexes. Application of Catalysis in the Cross-coupling Reaction of Aryl Ether and Aryl Grignard Reagent