- A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts
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The metal-free reduction of a range of phosphine(V) oxides employing oxalyl chloride as an activating agent and hexachlorodisilane as reducing reagent has been achieved under mild reaction conditions. The method was successfully applied to the reduction of industrial waste byproduct triphenylphosphine(V) oxide, closing the phosphorus cycle to cleanly regenerate triphenylphosphine(III). Mechanistic studies and quantum chemical calculations support the attack of the dissociated chloride anion of intermediated phosphonium salt at the silicon of the disilane as the rate-limiting step for deprotection. The exquisite purity of the resultant phosphine(III) ligands after the simple removal of volatiles under reduced pressure circumvents laborious purification prior to metalation and has permitted the facile formation of important transition metal catalysts.
- Kapu?niak, ?ukasz,Plessow, Philipp N.,Trzybiński, Damian,Wo?niak, Krzysztof,Hofmann, Peter,Jolly, Phillip Iain
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supporting information
p. 693 - 701
(2021/04/06)
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- Industrial-scale palladium-catalyzed coupling of aryl halides and amines - A personal account
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The palladium-catalyzed coupling of amines and aryl halides or aryl alcohol derivatives has matured from an exotic small-scale transformation into a very general, efficient and robust reaction during the last ten years. This article reports several applications of this method from an industrial vantage point, including ligand synthesis, synthesis of arylpiperazines, arylhydrazines and diarylamines. Much emphasis in placed on issues of scale-up and safety to underline the potential of C-N couplings as solutions for industrial-scale synthetic problems.
- Buchwald, Stephen L.,Mauger, Christelle,Mignani, Gerard,Scholz, Ulrich
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- Ligands for metals and improved metal-catalyzed processes based thereon
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One aspect of the present invention relates to ligands for transition metals. A second aspect of the present invention relates to the use of catalysts comprising these ligands in transition metal-catalyzed carbon-heteroatom and carbon-carbon bond-forming reactions. The subject methods provide improvements in many features of the transition metal-catalyzed reactions, including the range of suitable substrates, reaction conditions, and efficiency.
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- The Use of Catalytic Amounts of CuCl and Other Improvements in the Benzyne Route to Biphenyl-Based Phosphine Ligands
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Biphenyl-based phosphine ligands can be prepared on a significantly larger scale than previously possible as a result of the following discoveries and improvements to the original experimental procedure: the finding that CuCl catalyzes the coupling of hindered dialkylchlorophosphines with Grignard reagents; the development of conditions that permit ClPCy2 to be prepared and utilized in situ; the development of a more reliable large-scale preparation of 2-dimethylaminophenylmagnesium halide.
- Kaye, Steven,Fox, Joseph M.,Hicks, Frederick A.,Buchwald, Stephen L.
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p. 789 - 794
(2007/10/03)
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- Ligands for metals and improved metal-catalyzed processes based thereon
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One aspect of the present invention relates to novel ligands for transition metals. A second aspect of the present invention relates to the use of catalysts comprising these ligands in transition metal-catalyzed carbon-heteroatom and carbon-carbon bond-forming reactions. The subject methods provide improvements in many features of the transition metal-catalyzed reactions, including the range of suitable substrates, reaction conditions, and efficiency.
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- An Improved Synthesis of Functionalized Biphenyl-Based Phosphine Ligands
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Functionalized dicyclohexyl- and di-tert-butylphosphinobiphenyl ligands are prepared by the reaction of arylmagnesium halides with benzyne, followed by the addition of a chlorodialkylphosphine. This one-pot procedure is considerably less expensive and time-consuming than the method used previously to prepare such ligands. The cost of introducing the dicyclohexylphosphine group can be decreased by preparing chlorodicyclohexylphosphine from PCl3 and cyclohexylmagnesium chloride, and using the reagent without further purification. The new method is significant, as a variety of ligands can be produced in useful amounts by a procedure that is simple, with starting materials that are relatively inexpensive, and, in most cases, without chromatographic purification.
- Tomori, Hiroshi,Fox, Joseph M.,Buchwald, Stephen L.
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p. 5334 - 5341
(2007/10/03)
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