- PROCESS FOR PREPARING 2,6-DIALKYLPHENYLACETIC ACIDS
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The invention relates to a multi-stage process for preparing 2,6-dialkylphenylacetic acids of the general formula (I) by reacting 2,6-dialkylbromobenzenes with (1) magnesium, (2) a formamide, (3) an acid, (4) hydrogenation of the benzaldehyde obtained, (5
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Paragraph 0205-0213
(2022/01/04)
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- Cyclometalated iridium complexes of bis(aryl) phosphine ligands: Catalytic C-H/C-D exchanges and C-C coupling reactions
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This work details the synthesis and structural identification of a series of complexes of the (η5-C5Me5)Ir(III) unit coordinated to cyclometalated bis(aryl)phosphine ligands, PR′(Ar) 2, for R′ = Me and Ar = 2,4,6-Me3C6H 2, 1b; 2,6-Me2-4-OMe-C6H2, 1c; 2,6-Me2-4-F-C6H2, 1d; R′ = Et, Ar = 2,6-Me2C6H3, 1e. Both chloride-and hydride-containing compounds, 2b-2e and 3b-3e, respectively, are described. Reactions of chlorides 2 with NaBArF (BArF = B(3,5-C 6H3(CF3)2)4) in the presence of CO form cationic carbonyl complexes, 4+, with ν(CO) values in the narrow interval 2030-2040 cm-1, indicating similar π-basicity of the Ir(III) center of these complexes. In the absence of CO, NaBArF forces κ4-P,C,C′,C″ coordination of the metalated arm (studied for the selected complexes 5b, 5d, and 5e), a binding mode so far encountered only when the phosphine contains two benzylic groups. A base-catalyzed intramolecular, dehydrogenative, C-C coupling reaction converts the κ4 species 5d and 5e into the corresponding hydrido phosphepine complexes 6d and 6e. Using CD3OD as the source of deuterium, the chlorides 2 undergo deuteration of their 11 benzylic positions whereas hydrides 3 experience only D incorporation into the Ir-H and Ir-CH 2 sites. Mechanistic schemes that explain this diversity have come to light thanks to experimental and theoretical DFT studies that are also reported.
- Campos, Jesus,Espada, Maria F.,Lopez-Serrano, Joaquin,Carmona, Ernesto
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supporting information
p. 6694 - 6704
(2013/07/19)
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- Structural characterization of some new tris(2,6-dimethylphenyl)tin(iv) derivatives
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The triaryltin(IV) bromide (2,6-Me2C6H3)3SnBr (1) was prepared by treating SnCl4 with (2,6-Me2C6H3)MgBr. Exchange reactions between the bromide and KF or KOH afforded (2,6-Me2C6H3)3SnF (2) and (2,6-Me2C6H3)3SnOH (3). The solution behavior of compounds 1 - 3 was investigated by multinuclear (1H, 13C and 119Sn) NMR spectroscopy. Single-crystal X-ray diffraction analyses for compounds 1, 3 and 3·THF revealed that the coordination geometry around the metal atom is distorted tetrahedral.
- Barbul, Ioana,Varga, Richard A.,Silvestru, Cristian
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p. 313 - 319
(2013/04/24)
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- Axially chiral analogues of 4-(dimethylamino)pyridine: Novel catalysts for nonenzymatic enantioselective acylations
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A concise seven-step synthesis of atropisomeric 3-aryl analogues of DMAP from 4-pyridone 8 has been developed. A representative compound of this class, biaryl (±)-15, has been resolved using CSP HPLC and shown to be an efficient nucleophilic catalyst for kinetic resolution of a series of secondary alcohols on both an analytical and preparative scale (stereoselectivity factors, s = 8.9-29).
- Spivey, Alan C.,Fekner, Tomasz,Spey, Sharon E.
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p. 3154 - 3159
(2007/10/03)
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