Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Reexamination Certificate
2002-03-07
2003-06-24
Keys, Rosalynd (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
C560S102000, C568S315000, C568S316000, C568S631000, C568S642000, C570S127000, C570S182000, C585S469000, C585S471000
Reexamination Certificate
active
06583307
ABSTRACT:
REFERENCE TO A “MICROFICHE APPENDIX”
Not applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to Suzuki-Miyaura cross-coupling reactions. More particularly, the present invention relates to catalysts for Suzuki-Miyaura cross-coupling reactions.
2. General Background of the Invention
The Suzuki-Miyaura cross-coupling reaction, involving the coupling of an arylboronic acid with an organohalide, has proven to be an extremely useful synthetic tool in organic synthesis (1). Although palladium complexes bearing tertiary phosphine ligands are commonly employed (1a) (2), in Suzuki-Miyaura cross-couplings, these catalysts are often sensitive to air oxidation and therefore require air-free handling in order to minimize ligand oxidation. Nucleophilic N-heterocyclic carbenes, the imidazol-2-ylidenes, have recently been used as ancillary ligands for Suzuki-Miyaura cross-coupling reactions with great success (3).
In the specific area of coupling chemistry, catalytic systems which contain supporting ligations other than tertiary phosphine represent a scarcely explored area of investigation. Recently, a Pd(II) cyclometallated imine catalyst able to mediate both Suzuki (4) and Heck (5) reactions has been reported by Milstein. Unfortunately, this system requires high reaction temperatures and leads to products in modest yields.
Incorporated by reference are the paper attached to our U.S. Provisional Patent Application Serial No. 60/274,125 and entitled: “Convenient and Efficient Suzuki-Miyaura Cross-Coupling Catalyzed by a Palladium/Diazabutadiene System” by Gabriela A. Grasa, Anna C. Hillier, and Steven P. Nolan, all references cited therein, and all related papers of which the inventors are authors.
The following U.S. Patent is incorporated herein by reference:
U.S. Pat. No. 6,316,3 80 entitled “Catalyst system comprising transition metal and imidazoline-2-ylidene or imidazolidine-2-ylidene”
BRIEF SUMMARY OF THE INVENTION
The present invention includes a Pd(OAc)
2
/diazabutadiene system for the catalytic cross-coupling of aryl halides with arylboronic acids and a method of catalytic cross-coupling of aryl halides with arylboronic acids using this system.
DETAILED DESCRIPTION OF THE INVENTION
Based on the Milstein report, we thought a well-known family of ligands, the diazabutadienes, might possibly mediate the Suzuki-Miyaura reaction. The chelating nature of these ligands might also assist in stabilizing catalytic species. Ligands containing the 1,4-diaza-1,3-butadiene skeleton, a-diimines, (DAB-R, Scheme 1—see below) have been known for quite some time (6). The coordination versatility of these ligands, a consequence of the flexibility of the NCCN backbone and the strong s-donor and p-acceptor properties, reflects a very important feature of DAB-R-metal complexes (7). Few investigations have focused on the influence of DAB-R as a supporting ligand in catalytic processes. The most notable exceptions have been the use of metal-diimine complexes to mediate olefin polymerization (8) and alkyne cyclotrimerization (9) processes.
REFERENCES:
patent: 5147840 (1992-09-01), de Jong et al.
patent: 6194599 (2001-02-01), Miller et al.
patent: 6235849 (2001-05-01), Jayaraman et al.
patent: 6316380 (2001-11-01), Nolan et al.
Grasa et al., Convenient and Efficient Suzuki-Miyaura Cross-Coupling Catalyzed by a Palladium/Diazabutadiene System, Organic Letters, Feb. 2001, vol. 3, No. 7, pp. 1077-1080.
Grasa Gabriela
Nolan Steven P.
Garvey, Smith, Nehrbass & Doody, L.L.C.
Keys Rosalynd
Nehrbass Seth M.
University of New Orleans Research and Technology Foundation, In
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