- Barbier–Negishi Coupling of Secondary Alkyl Bromides with Aryl and Alkenyl Triflates and Nonaflates
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A mild and practical Barbier–Negishi coupling of secondary alkyl bromides with aryl and alkenyl triflates and nonaflates has been developed. This challenging reaction was enabled by the use of a very bulky imidazole-based phosphine ligand, which resulted in good yields as well as good chemo- and site selectivities for a broad range of substrates at room temperature and under non-aqueous conditions. This reaction was extended to primary alkyl bromides by using an analogous pyrazole-based ligand.
- Zhang, Ke-Feng,Christoffel, Fadri,Baudoin, Olivier
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supporting information
p. 1982 - 1986
(2018/02/06)
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- Terminal-Selective Functionalization of Alkyl Chains by Regioconvergent Cross-Coupling
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Hydrocarbons are still the most important precursors of functionalized organic molecules, which has stirred interest in the discovery of new C?H bond functionalization methods. We describe herein a new step-economical approach that enables C?C bonds to be constructed at the terminal position of linear alkanes. First, we show that secondary alkyl bromides can undergo in situ conversion into alkyl zinc bromides and regioconvergent Negishi coupling with aryl or alkenyl triflates. The use of a suitable phosphine ligand favoring Pd migration enabled the selective formation of the linear cross-coupling product. Subsequently, mixtures of secondary alkyl bromides were prepared from linear alkanes by standard bromination, and regioconvergent cross-coupling then provided access to the corresponding linear arylation product in only two steps.
- Dupuy, Stéphanie,Zhang, Ke-Feng,Goutierre, Anne-Sophie,Baudoin, Olivier
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supporting information
p. 14793 - 14797
(2016/11/23)
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- Iron(III) amine-bis(phenolate) complexes as catalysts for the coupling of alkyl halides with aryl Grignard reagents
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Catalytic cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing β-hydrogens is achieved using Fe(III) amine-bis(phenolate) halide complexes. The Royal Society of Chemistry.
- Chowdhury, Rajoshree Roy,Crane, Angela K.,Fowler, Candace,Kwong, Philip,Kozak, Christopher M.
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- COMPOUNDS FOR INHIBITING KSP KINESIN ACTIVITY
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The present invention provides compounds of Formula (I) (wherein R1, R3, X, W, Z and ring Y are as defined herein). The present invention also provides compositions comprising these compounds that are useful for treating cellular proliferative diseases or disorders associated with KSP kinesin activity and for inhibiting KSP kinesin activity.
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Page/Page column 89; 90
(2010/11/23)
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- Steric and Stereoelectronic Effects in the Hydrogenolysis and Birch Reduction of Some Hindered Tertiary-Benzylic Carbinols
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3-(4'-Methoxyphenyl)pentan-3-ol (3a) and 3-(4'-methoxyphenyl)-2,4-dimethylpentan-3-ol (3b) underwent catalytic hydrogenolysis over 10percent palladium/charcoal at moderate temperatures and pressures.The more hindered tertiary-benzylic carbinols 3-(4'-methoxyphenyl)-2,2,4-trimethylpentan-3-ol (6), 3-(4'-methoxyphenyl)-2,2,4,4-tetramethylpentan-3-ol (3c), 1-(4'-methoxyphenyl)-2,2,6,6-tetramethylcyclohexan-1-ol (8) and 1-(1',1'-dimethylethyl)-6-methoxy-2,2-dimethyl-1,2,3,4-tetrahydronaphthalen-1-ol (10) were completely resistant to hydrogenolysis, even under vigorous conditions.While the hindered tertiary-benzylic carbinols (6), (8) and (10) readily underwent Birch reduction, the analogous di-t-butyl anisyl carbinol (3c) was unchanged.The failure of (3c) to undergo Birch reduction is probably due to a hitherto unrecognized stereoelectronic effect: the C-OH bond of (3c) is constrained to lie more or less in the plane of the benzene ring, and addition of an electron to the benzene ring of the derived oxyanion (31) is inhibited in this conformation.
- Collins, David J.,Jacobs, Howard A.
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p. 1989 - 2004
(2007/10/02)
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