Late transition metal catalyzed C-N and C-C bond forming reactions

New methods for the palladium-catalyzed amination of aryl halides are described. Key to these is the development of new catalysts and reaction conditions for these transformations. Initially, P(o-tol)3 ligated palladium catalysts were investigated but gave way to systems that used chelating phosphine ligands which substantially expanded the scope of the catalytic amination methodology. Palladium catalyst systems based on BINAP ((2,2'-diphenylphosphino)-1, 1 '-binaphthyl) allowed for the transformation of a much wider range of amines and aryl halide substrates, as well as aryl triflates. Of practical significance was that the use of cesium carbonate as a base at 100 °C substantially increased the functional group tolerance of the method. Palladium catalysts supported by novel, bulky, electron-rich phosphine ligands are exceptionally effective in the C-N, C-0, and C-C coupling procedures. For some substrate combinations, these palladium catalysts are effective for the room-temperature catalytic amination of aryl chlorides. These palladium catalysts are also highly effective for Suzuki coupling reactions of aryl bromides and chlorides at room temperature. Suzuki coupling reactions of aryl bromides and aryl chlorides are effective at very low catalyst loadings (0.000001-0.005 mol % Pd for ArBr, 0.02-0.05 mol % for ArCI) at 100 °C, and reactions of hindered aryl halides or boronic acids are effected at moderate catalyst loadings (1 mol % Pd). The high reactivity of these catalysts towards aryl chlorides challenges the conventional dogma that chloride substrates cannot be transformed under mild conditions with palladium catalysts, and significantly expands the pool of substrates available for cross-coupling chemistry.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Chemistry

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1999

Author dc:creator

• Wolfe, John P. (John Perry), 1970-

Advisor dc:contributor.advisor

• Stephen L. Buchwald.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/9521

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/9521