2026-09-19T08:06:05Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/296392022-01-13T07:54:21Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022
Stephen L. Buchwald.
Huang, Xiaohua, 1973-
Massachusetts Institute of Technology. Dept. of Chemistry.
Massachusetts Institute of Technology. Department of Chemistry
2006-03-24T16:10:30Z
2006-03-24T16:10:30Z
2003
2003
http://hdl.handle.net/1721.1/29639
53399636
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2003.
Vita.
Includes bibliographical references.
New methods for Pd-catalyzed cross-coupling reactions of aryl halides or arenesulfonates are described. Key to the success of these transformations is the proper choice of ligand and reaction conditions. Palladium catalysts supported by bulky, monodentate phosphine ligands with a biaryl backbone or the bidentate ligand, Xantphos, effectively promote the formation of ca-aryl carbonyl compounds. Base-sensitive functional groups are better tolerated when a weak base, such as K3PO4, is used. One of the most difficult transformations in Pd catalysis, the intermolecular C-O bond formation between primary alcohols and electron-neutral or even electron-rich aryl halides, was effectively promoted by the use of a new generation of ligands, 3-methyl-2-di-t-butylphosphinobiaryl. The one-step synthesis of ligands from cheap starting materials, as well as the mild reaction conditions employed for the coupling reactions, enables the practical use of Pd catalysis to access aryl alkyl ethers for the first time. Continuing study of Pd-catalyzed C-N bond-forming processes using biaryl monophosphine ligands led to the discovery of a structural derivative of these ligands, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl. This ligand, in combination with a Pd source, produces a catalyst system with both a greater degree of activity and of stability than those that use our previous ligands. Substrates that were not amenable to Pd catalysis previously are reexamined using this new catalyst system, and excellent results are obtained.
by Xiaohua Huang.
Ph.D.
216 leaves
6636696 bytes
6636505 bytes
application/pdf
application/pdf
eng
Massachusetts Institute of Technology
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http://dspace.mit.edu/handle/1721.1/7582
Chemistry.
Palladium-catalyzed C-C, C-N and C-O bond formation
Palladium-catalyzed carbon-carbon, carbon-nitrogen and carbon-oxygen bond formation
Thesis
application/pdf
Publication
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unknown
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<Abstract>New methods for Pd-catalyzed cross-coupling reactions of aryl halides or arenesulfonates are described. Key to the success of these transformations is the proper choice of ligand and reaction conditions. Palladium catalysts supported by bulky, monodentate phosphine ligands with a biaryl backbone or the bidentate ligand, Xantphos, effectively promote the formation of ca-aryl carbonyl compounds. Base-sensitive functional groups are better tolerated when a weak base, such as K3PO4, is used. One of the most difficult transformations in Pd catalysis, the intermolecular C-O bond formation between primary alcohols and electron-neutral or even electron-rich aryl halides, was effectively promoted by the use of a new generation of ligands, 3-methyl-2-di-t-butylphosphinobiaryl. The one-step synthesis of ligands from cheap starting materials, as well as the mild reaction conditions employed for the coupling reactions, enables the practical use of Pd catalysis to access aryl alkyl ethers for the first time. Continuing study of Pd-catalyzed C-N bond-forming processes using biaryl monophosphine ligands led to the discovery of a structural derivative of these ligands, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl. This ligand, in combination with a Pd source, produces a catalyst system with both a greater degree of activity and of stability than those that use our previous ligands. Substrates that were not amenable to Pd catalysis previously are reexamined using this new catalyst system, and excellent results are obtained.</Abstract>
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