Novel Palladium鈥揂minocarbene Species Derived from Metal-Mediated Coupling of Isonitriles and 1,3-Diiminoisoindoline: Synthesis and Catalytic Application in Suzuki鈥揗iyaura Cross-Coupling

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• 作者：Rog茅rio S. Chay ; Konstantin V. Luzyanin ; Vadim Yu. Kukushkin ; M. F谩tima C. Guedes da Silva ; Armando J. L. Pombeiro
• 刊名：Organometallics
• 出版年：2012
• 出版时间：March 26, 2012
• 年：2012
• 卷：31
• 期：6
• 页码：2379-2387
• 全文大小：375K
• 年卷期：v.31,no.6(March 26, 2012)
• ISSN：1520-6041

文摘

The reaction between metal-bound isonitriles in cis-[PdCl₂(CNRp>1p>)₂] [Rp>1p> = cyclohexyl (Cy) 1, Bup>tp>2, C₆H₄(2,6-Me₂) (Xyl) 3, CMe₂CH₂CMe₃4] and 1,3-diiminoisoindoline (9) in CHCl₃ under reflux for 4 h provides the carbene species [Pd{C(N鈺怌p>ap>(C₆H₄CNHNp>bp>))鈺怤(H)Rp>1p>}₂]p>a鈭?i>bp> (Rp>1p> = Cy 10, 82% isolated yield) or cis-[PdCl{C(N鈺怌p>ap>(C₆H₄CNHNp>bp>))鈺怤(H)Rp>1p>}(CNRp>1p>)]p>a鈭?i>bp> (Rp>1p> = Bup>tp>11, 78%; Xyl 12, 84%; CMe₂CH₂CMe₃13, 79%), derived from the addition of two or one equivs of 9 to the starting 1鈥?b>4, respectively. The corresponding integration of cis-[PdCl₂(CNRp>1p>)(PPh₃)] (Rp>1p> = Cy 5, Bup>tp>6, CMe₂CH₂CMe₃8) with 1 equiv of 9 in CHCl₃ under reflux for 4 h affords the carbene species cis-[PdCl{C(N鈺怌p>ap>(C₆H₄CNHNp>bp>))鈺怤(H)Rp>1p>}(PPh₃)]p>a鈭?i>bp> (Rp>1p> = Cy 14, 84%; Bup>tp>15, 76%; CMe₂CH₂CMe₃16, 75%). Complexes 10鈥?b>16 were characterized by elemental analyses (C, H, N), ESIp>+p>-MS, IR, and 1D (p>1p>H, p>13p>C{p>1p>H}) and 2D (p>1p>H,p>1p>H-COSY, p>1p>H,p>13p>C-HMQC/p>1p>H,p>13p>C-HSQC, p>1p>H,p>13p>C-HMBC) NMR spectroscopies. In addition, the structures of aminocarbene complexes 10 and 12 were elucidated by X-ray diffraction. The catalytic properties of 10鈥?b>16 in the Suzuki鈥揗iyaura cross-coupling of aryl halides, viz., 4-Rp>2p>C₆H₄X (X = I, Rp>2p> = OMe; X = Br, Rp>2p> = Me, OMe, and NO₂), with phenylboronic acid (in EtOH as solvent, K₂CO₃ or Cs₂CO₃ as base, 80 掳C) yielding biaryl species 4-Rp>2p>C₆H₄Ph, were evaluated. Complexes 14鈥?b>16 exhibit a high catalytic activity (yields up to 98%, TONs up to 9.8 脳 10p>4p>, TOFs up to 3.9 脳 10p>4p>).