Synthesis of 2,6-bis(2-oxazolinyl)phenylplatinum(II) NCN pincer complexes by direct cyclometalation. Catalysts for carbon-carbon bond formation

被引:77
作者
Fossey, JS [1 ]
Richards, CJ [1 ]
机构
[1] Queen Mary Univ London, Dept Chem, London E1 4NS, England
关键词
D O I
10.1021/om0305162
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
1,3-Bis(4',4'-dimethyl-2'-oxazolinyl)benzene (5a) and 5-nitro-1,3-bis(4',4'-dimethyl-2'-oxazolinyl)benzene (5b) were heated in dry acetic acid with K2PtCl4 to give the corresponding 2,6-bis(4',4'-dimethyl-2'-oxazolinyl)phenylplatinum(II) chloride complexes 6a and 6b in 49 and 11% yield, respectively. The X-ray structure of 6b is reported. The main side product observed in the platination of 5a was identified as di(2-methyl-2-N-acetyl)propyl isoplithalate. In contrast, use of Pd(OAc)(2) with 5a in this protocol, followed by addition of LiBr, gave 2,6-bis(4',4'-dimethyl-2'-oxazolinyl)phenylpalladium(II) bromide in only 3% yield. Treatment of 6a with AgOTf and AgSbF6 in acetone gave quantitatively the corresponding cationic 2,6-bis(4',4'-dimethyl-2'-oxazolinyl)phenyl(aquo)platinum(II) complexes 15a and 15b. Similarly treatment of 6b with AgOTf in acetone gave 4-nitro-2,6-bis(4',4'-dimethyl-2'-oxazolinyl)phenyl(aquo)platinum(II) trifluoromethanesulfonate (15c) (72%). Complexes 15a-c, together with 2,6-bis(4',4'-dimethyl-2'-oxazolinyl)phenylaquopalladium(II) triflate (15d), were applied as catalysts for the Michael reaction between methyl vinyl ketone and ethyl cyanoacetate and the Diels-Alder reaction between acrylonitrile and cyclopentadiene. In both cases platinum complex 15a was found to be the most active, with the 4-nitro group of 15c resulting in decreased catalytic activity.
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页码:367 / 373
页数:7
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共 35 条
[1]  
Albrecht M, 2001, ANGEW CHEM INT EDIT, V40, P3750, DOI 10.1002/1521-3773(20011015)40:20<3750::AID-ANIE3750>3.0.CO
[2]  
2-6
[3]   Chiral platinum and palladium complexes containing functionalized C2-symmetric bisaminoaryl 'Pincer' ligands [J].
Albrecht, M ;
Kocks, BM ;
Spek, AL ;
van Koten, G .
JOURNAL OF ORGANOMETALLIC CHEMISTRY, 2001, 624 (1-2) :271-286
[4]   KINETICS OF REACTION OF ALKYL AND ARYL COMPOUNDS OF NICKEL GROUP WITH PYRIDINE [J].
BASOLO, F ;
PEARSON, RG ;
CHATT, J ;
GRAY, HB ;
SHAW, BL .
JOURNAL OF THE CHEMICAL SOCIETY, 1961, (MAY) :2207-&
[5]   Divergent behavior of palladium(II) and platinum(II) in the metalation of 1,3-di(2-pyridyl)benzene [J].
Cárdenas, DJ ;
Echavarren, AM ;
de Arellano, MCR .
ORGANOMETALLICS, 1999, 18 (17) :3337-3341
[6]   SYNTHESIS AND REACTIONS OF CYCLOPALLADATED COMPOUNDS DERIVED FROM N,N'-DIALKYLBENZENE-1,3-DICARBALDIMINES [ALKYL = ETHYL (H2L1), BUTYL OR OCTYL] AND N,N'-DIBENZYL-BENZENE-1,3-DICARBALDIMINE - CRYSTAL-STRUCTURE OF [PD2L1(PY)4][CLO4]2 (PY = PYRIDINE) [J].
CHAKLADAR, S ;
PAUL, P ;
VENKATSUBRAMANIAN, K ;
NAG, K .
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1991, (10) :2669-2676
[7]   ORGANODIPALLADIUM(II) CYCLOMETALLATES OF THE SCHIFF-BASE N,N'-DIETHYL-2,6-DIALDIMINOBENZENE [J].
CHAKLADAR, S ;
PAUL, P ;
NAG, K .
POLYHEDRON, 1991, 10 (13) :1513-1519
[8]   THE LEWIS ACID COMPLEXES OF ALPHA,BETA-UNSATURATED CARBONYL AND NITRILE COMPOUNDS .1. A NUCLEAR MAGNETIC-RESONANCE STUDY [J].
CHILDS, RF ;
MULHOLLAND, DL ;
NIXON, A .
CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE, 1982, 60 (06) :801-808
[9]   Cyclopropanation with diazomethane and bis(oxazoline)palladium(II) complexes [J].
Denmark, SE ;
Stavenger, RA ;
Faucher, AM ;
Edwards, JP .
JOURNAL OF ORGANIC CHEMISTRY, 1997, 62 (10) :3375-3389
[10]  
Dijkstra HP, 2003, EUR J INORG CHEM, P830