- Coordination Chemistry of Borane in Solution: Application to a STING Agonist
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Equilibrium constants were determined for ligand exchange reactions of borane complexes with various oxygen, sulfur, nitrogen, and phosphorus nucleophiles in solution, and a binding affinity scale was built spanning a range of 12 orders of magnitude. While the Keq are minimally dependent on the solvent, the rate of ligand exchange varies significantly. The fastest and slowest rates were observed in THF and CDCl3, respectively. Moreover, the ligand exchange rate differs in a very broad range depending on stability of the starting complex. Binding of BH3 was found to be much more sensitive to steric factors than protonation. Comparing nitrogen bases having equal steric properties, a linear correlation of BH3 binding affinity vs. Br?nsted acidity was found. This correlation can be used to quickly estimate the BH3 binding affinity of a substrate if pKa is known. Kinetic studies suggest the ligand exchange to occur as a bimolecular SN2 reaction unless other nucleophilic species were present in the reaction mixture.
- Lemaire, Sébastien,Zhdanko, Alexander,van der Worp, Boris A.
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- Method for synthesizing 2-dicyclohexylphosphine-2 ', 4', 6 '-triisopropyl biphenyl
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The invention discloses a method for synthesizing 2-dicyclohexylphosphine-2 ', 4', 6 '-triisopropyl biphenyl, and belongs to the field of organic synthesis. According to the method, fluorobenzene is used as a raw material, is reacted with an organic lithium reagent in an anhydrous and anaerobic atmosphere, then is reacted with dicyclohexylchlorophosphine, and finally is reacted with 2, 4, 6-triisopropylphenyl lithium to generate 2-dicyclohexylphosphine-2 ', 4', 6 '-triisopropyl biphenyl. Compared with the prior art, the method has the advantages of easily available raw materials, simple post-treatment and high product yield, and is more suitable for industrialized production.
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Paragraph 0016-0024
(2020/07/15)
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- Method for preparing 2-dicyclohexylphosphine-2,4,6-di-iso-propylbiphenyl
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The invention discloses a method for preparing 2-dicyclohexylphosphine-2,4,6-di-iso-propylbiphenyl. The method comprises the following steps of performing low-temperature lithiation on 2-halogen-2,4,6-di-iso-propylbiphenyl, and reacting the lithiated 2-halogen-2,4,6-di-iso-propylbiphenyl with dicyclohexylchlorophosphine. The method disclosed by the invention has the advantages of high yield, simplicity in aftertreatment and easiness in operation. An optimized implementation scheme according to the method disclosed by the invention comprises the following steps of taking 2,4,6-triisopropyl halo-benzene as an initial raw material, performing low-temperature lithiation, and reacting with o-dihalo-benzene to obtain the 2-halogen-2,4,6-di-iso-propylbiphenyl; continuously performing the low-temperature lithiation, and reacting with the dicyclohexylchlorophosphine so as to prepare the 2-dicyclohexylphosphine-2,4,6-di-iso-propylbiphenyl. The method disclosed by the invention has the advantages that the raw material is easily obtained, the operation is simple, products with high yield and high purity can be obtained, and the method is especially suitable for large-scale industrialized production.
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Paragraph 0059
(2016/11/17)
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- Improved syntheses of phosphine ligands by direct coupling of diarylbromophosphine with organometallic reagents
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Br versus Cl: It is found that the use of diarylbromophosphines instead of diarylchlorophosphines is crucial for their direct coupling with binaphthylmagnesium bromide or BINOL triflate. This finding has led to an improved preparation of both electron-deficient BINAP-type phosphine ligands and several important Buchwald's ligands. Copyright
- Liu, Lei,Wu, Hai-Chen,Yu, Jin-Quan
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supporting information; experimental part
p. 10828 - 10831
(2011/11/04)
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- An efficient and safe procedure for the large-scale Pd-catalyzed hydrazonation of aromatic chlorides using buchwald technology
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A convenient, optimized and safe synthesis of N-arylhydrazines, useful as intermediates for active ingredients in agricultural and pharmaceutical applications, is reported. Starting from aryl halides (chlorides and bromides), a palladium-catalyzed carbon-nitrogen coupling reaction followed by an acidic treatment afforded the target molecules in good to excellent yields using low catalyst loadings. This technology has then been successfully applied on a large scale in a pilot plant. This contribution also describes the major improvements in ligand synthesis and the thermal data required to develop a process on a pilot scale.
- Mauger, Christelle C.,Mignani, Gerard A.
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p. 1065 - 1071
(2013/09/03)
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- Expanding Pd-catalyzed C-N bond-forming processes: The first amidation of aryl sulfonates, aqueous amination, and complementarity with Cu-catalyzed reactions
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The first general method for the Pd-catalyzed amination of aryl tosylates and benzenesulfonates was developed utilizing ligand 1, which belongs to a new generation of biaryl monophosphine ligands. In addition, the new catalyst system for the first time enables amidation of aryl arenesulfonates and aqueous amination protocols that do not necessitate the use of cosolvents. The substrate scope has been significantly expanded to include aryl halides containing primary amides and free carboxylic acid groups. In the case of multifunctional substrates, the Pd-catalyzed amination can provide selectivity that is complementary to the Cu-catalyzed C-N bond-forming processes. Copyright
- Huang, Xiaohua,Anderson, Kevin W.,Zim, Danilo,Jiang, Lei,Klapars, Artis,Buchwald, Stephen L.
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p. 6653 - 6655
(2007/10/03)
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