Copper catalyzed reaction of Grignard reagents with chloromagnesium salts of -bromoacids

Baer, Ted A.; Carney, Robert L.

doi:10.1016/s0040-4039(00)92999-x

Cited by 41 publications

(10 citation statements)

References 2 publications

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“…Reduction of (−)‐ 5 with lithium aluminum hydride gave alcohol (−)‐ 7 (88%) that was transformed into bromide (−)‐ 8 in 84% yield by reaction with CBr 4 /PPh 3 18. The side chain was completed by copper‐catalyzed cross coupling using a procedure developed by Baer and Carney 19. Thus, 11‐bromoundecanoic acid was treated with methyl magnesium chloride to give the corresponding salt that was reacted (catalyst: 3.5 mol % of Li 2 CuCl 4 )20 with the Grignard reagent prepared by treatment of (−)‐ 8 with magnesium (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Syntheses of Enantiomerically Pure Cyclopent‐2‐ene‐1‐carboxylic Acid and (Cyclopent‐2‐enyl)acetic Acid by Enantioselective Palladium‐Catalyzed Allylic Alkylations − Synthesis of Enantiomerically Pure (−)‐Chaulmoogric Acid

et al. 2003

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Asymmetric Pd-catalyzed allylic alkylations of dimethyl malonate and diethyl 2-acetoxymalonate with 3-chlorocyclopentene, using phosphanyloxazolines 1 and ent-1 as chiral ligands, gave products (−)-2 and (+)-3b with 95 and 99.5% ee, respectively. Oxidative degradation of (+)-3b furnished (+)-(R)-cyclopent-2-ene-1-carboxylic acid [(+)-4] with Ͼ 99% ee. Alkylation product (−)-2 was transformed into enantio-

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Section: Resultsmentioning

confidence: 99%

Syntheses of Enantiomerically Pure Cyclopent‐2‐ene‐1‐carboxylic Acid and (Cyclopent‐2‐enyl)acetic Acid by Enantioselective Palladium‐Catalyzed Allylic Alkylations − Synthesis of Enantiomerically Pure (−)‐Chaulmoogric Acid

et al. 2003

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“…Palmitic acid (H-n16:0) and palmitic acid-d 31 (D-n16:0) were obtained from Sigma–Aldrich. 12-Methyltetradecanoic acid (H-a15:0) was purchased from Sigma–Aldrich or prepared from s -butyl magnesium chloride (Sigma–Aldrich) and 11-bromoundecanoic acid (Sigma–Aldrich) according to the method of Baer and Carney[ 64 ] and purified by vacuum distillation. Perdeuterated D-a15:0 was prepared from H-a15:0 through 3 cycles of H/D exchange with D 2 O catalyzed by 10% Pt/C at 220°C as described by Yepuri et al,[ 65 ] followed by chromatography on silica gel and vacuum distillation.…”

Section: Methodsmentioning

confidence: 99%

The in vivo structure of biological membranes and evidence for lipid domains

et al. 2017

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Examining the fundamental structure and processes of living cells at the nanoscale poses a unique analytical challenge, as cells are dynamic, chemically diverse, and fragile. A case in point is the cell membrane, which is too small to be seen directly with optical microscopy and provides little observational contrast for other methods. As a consequence, nanoscale characterization of the membrane has been performed ex vivo or in the presence of exogenous labels used to enhance contrast and impart specificity. Here, we introduce an isotopic labeling strategy in the gram-positive bacterium Bacillus subtilis to investigate the nanoscale structure and organization of its plasma membrane in vivo. Through genetic and chemical manipulation of the organism, we labeled the cell and its membrane independently with specific amounts of hydrogen (H) and deuterium (D). These isotopes have different neutron scattering properties without altering the chemical composition of the cells. From neutron scattering spectra, we confirmed that the B. subtilis cell membrane is lamellar and determined that its average hydrophobic thickness is 24.3 ± 0.9 Ångstroms (Å). Furthermore, by creating neutron contrast within the plane of the membrane using a mixture of H- and D-fatty acids, we detected lateral features smaller than 40 nm that are consistent with the notion of lipid rafts. These experiments—performed under biologically relevant conditions—answer long-standing questions in membrane biology and illustrate a fundamentally new approach for systematic in vivo investigations of cell membrane structure.

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“…2-bromo-propane was transformed into its Grignard compound and coupled with 1-bromo-tetradecane in the presence of a copperlithium catalyst (mixture of LiC1 and CuC12). The product was purified by distillation [20,21].…”

Section: Chemical Synthesis and Samples Preparationmentioning

confidence: 99%

The stabilization of unusual conformers in guest-host systems: Solid-state NMR investigations of 2-methylhexadecane in urea and thiourea

et al. 2004

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Solid-state nuclear magnetic resonance (NMR) spectroscopy is employed for the first time on urea and thiourea inclusion compounds (UICs and TICs) containing branched alkyl chains. In the present work, 2H and t3C NMR as well as X-ray diffraction studies of two selectively deuterated 2-methylhexadecanes in UIC and TIC are presented. An analysis of the derived T~ data reveals significant differences between UICs and TICs, which can be attributed to differences in the motional features of the guest species. It is found that four different motionaI contributions have to be considered, namely, chain rotation, chain wobbling, trans-gauche isomerization and methyl group rotation. 2-Methylhexadecane in UIC exists in ah almost all-trans conformation (gauche amount not more than 5%) and undergoes fast chain rotation (6-site jump process, activation energy E A = 16.7 kJ/mol). The analysis of the 2H NMR spectra of 2-methylhexadecane-l,l',2-d 7 in urea proves that the branched chain end exists in ah eclipsed conformation. The T~ data of 2-methylhexadecane-3-d 2 in thiourea can be reproduced by an overall rotation (E A = 9.8 kJ/mol) a n d a trans-gauche isomerization with torsional jumps around the C-3-C-4 bond (E A = 11.0 kJ/mol, gauche population = 15%). As for the corresponding UIC, the 2H NMR spectra of 2-methylhexadecane-l,l',2-d 7 in TIC can be only explained by the existence of an eclipsed conformation at the branched chain end.

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Copper catalyzed reaction of Grignard reagents with chloromagnesium salts of -bromoacids

Cited by 41 publications

References 2 publications

Syntheses of Enantiomerically Pure Cyclopent‐2‐ene‐1‐carboxylic Acid and (Cyclopent‐2‐enyl)acetic Acid by Enantioselective Palladium‐Catalyzed Allylic Alkylations − Synthesis of Enantiomerically Pure (−)‐Chaulmoogric Acid

Syntheses of Enantiomerically Pure Cyclopent‐2‐ene‐1‐carboxylic Acid and (Cyclopent‐2‐enyl)acetic Acid by Enantioselective Palladium‐Catalyzed Allylic Alkylations − Synthesis of Enantiomerically Pure (−)‐Chaulmoogric Acid

The in vivo structure of biological membranes and evidence for lipid domains

The stabilization of unusual conformers in guest-host systems: Solid-state NMR investigations of 2-methylhexadecane in urea and thiourea

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