- 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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- Highly chemoselective Mono-Suzuki arylation reactions on all three dichlorobenzene isomers and applications development
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A Pd catalyst system is described that allows very high chemoselective monoarylation on all three isomers of dichlorobenzene. Direct application of these commodity chemicals to high-value ligands, anilines, azides, and carbazoles was achieved through this process discovery.
- Ullah, Ehsan,McNulty, James,Robertson, Al
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p. 2127 - 2131
(2012/06/01)
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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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- 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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- Highly active palladium catalysts for Suzuki coupling reactions
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Mixtures of palladium acetate and o-(di-tert-butylphosphino)biphenyl (4) catalyze the room-temperature Suzuki coupling of aryl bromides and aryl chlorides with 0.5-1.0 mol % Pd. Use of o-(dicyclohexylphosphino)biphenyl (2) allows Suzuki couplings to be carried out at low catalyst loadings (0.000001-0.02 mol % Pd). The process tolerates a broad range of functional groups and substrate combinations including the use of sterically hindered substrates. This is the most active catalyst system in terms of reaction temperature, turnover number, and steric tolerance which has been reported to date.
- Wolfe, John P.,Singer, Robert A.,Yang, Bryant H.,Buchwald, Stephen L.
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p. 9550 - 9561
(2007/10/03)
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