- Efficient cross-coupling of aryl/alkenyl triflates with acyclic secondary alkylboronic acids
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Aryl-secondary alkyl cross-coupling with aryl sulfonate esters as coupling partners remains a significant challenge. Efficient cross-coupling between aryl/alkenyl triflates and acyclic secondary alkylboronic acids is realized for the first time to provide a series of sterically congested acyclic secondary alkyl arenes/olefins in good to excellent yields. The employment of sterically bulky P,PO ligand L1/L2 is crucial for the high yields and selectivities. The method has enabled a concise and 4-step synthesis of a key intermediate of male contraceptive agent and PAF antagonist gossypol.
- Si, Tengda,Li, Bowen,Xiong, Wenrui,Xu, Bin,Tang, Wenjun
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supporting information
p. 9903 - 9909
(2017/12/12)
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- IRON BISPHENOLATE COMPLEXES AND METHODS OF USE AND SYNTHESIS THEREOF
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The present application, relates to iron bisphenolate complexes and methods of use and synthesis thereof. The iron complexes are prepared from tridentate or tetradentate ligands of Formula I: wherein R1 and R2 are as defined herein. Also provided are methods and processes of using the iron bisphenolate complexes as catalysts in cross-coupling reactions and in controlled radical polymerizations.
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Paragraph 00187-00191
(2013/04/25)
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- Catalytic alkylation of aryl Grignard reagents by iron(iii) amine-bis(phenolate) complexes
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Reaction of n-propylamino-N,N-bis(2-methylene-4-tert-butyl-6-methylphenol), H2L1, n-propylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol), H2L2, and benzylamino-N,N-bis(2-methylene-4-tert-butyl-6- methylphenol), H2L3, with anhydrous ferric chloride in the presence of base yields the products, [FeL1(μ-Cl)]2 (1), [FeL2(μ-Cl)]2 (2) and [FeL3(μ-Cl)]2 (3). In the solid state, these complexes exist as chloride-bridged dimers giving distorted trigonal bipyramidal iron(iii) ions. Reaction of H2L1 with FeBr 3, however, results in the formation of a tetrahedral iron(iii) complex possessing two bromide ligands. The amine-bis(phenolate) ligand is bidentate in this complex and bonds to the iron(iii) ion via the phenolate O-donors. The central amine donor is protonated, resulting in a quaternized ammonium fragment and the iron(iii) centre possesses a negative formal charge. As a result, this complex is zwitterionic and formulated as FeBr2L1H (4). Complex 1 is an air-stable, non-hygroscopic, single-component catalyst for C-C cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides, including chlorides. Good to excellent yields of cross-coupled products are obtained in diethyl ether at room temperature. In some cases where low yields are obtained under these conditions, the use of microwave-assisted heating of the reaction mixture can improve yields. The Royal Society of Chemistry 2011.
- Qian, Xin,Dawe, Louise N.,Kozak, Christopher M.
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experimental part
p. 933 - 943
(2011/04/23)
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