The Utility of Phosphonate Carbanions in Olefin Synthesis

Wadsworth, William S.; Emmons, William D.

doi:10.1021/ja01468a042

Cited by 1,354 publications

(553 citation statements)

References 1 publication

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“…Purification was done by chromatography on silica gel, eluting with 2% ethyl acetate in hexanes to give 3.65 g of octadecanal to give 78% yield. The C 20 olefin was formed by coupling with the ethyl ester of diethylphosphonoacetic acid (31) with potassium hexamethyldisilazane as the base (32). Potassium hexamethyldisilazane (0.5 M in 2.3 ml of toluene) was added to a solution of the ethyl ester of diethylphosphonoacetic acid (11.62 mmol) and 18-crown-6 (52.9mmol) in 100 ml of anhydrous tetrahydrofuran at Ϫ78°C.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Dideoxymycobactin Antigens Presented by CD1a Reveals T Cell Fine Specificity for Natural Lipopeptide Structures

Young

Kasmar

Moraski

et al. 2009

Journal of Biological Chemistry

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Mycobacterium tuberculosis survival in cells requires mycobactin siderophores. Recently, the search for lipid antigens presented by the CD1a antigen-presenting protein led to the discovery of a mycobactin-like compound, dideoxymycobactin (DDM). Here we synthesize DDMs using solution phase and solid phase peptide synthesis chemistry. Comparison of synthetic standards to natural mycobacterial mycobactins by nuclear magnetic resonance and mass spectrometry allowed identification of an unexpected ␣-methyl serine unit in natural DDM. This finding further distinguishes these pre-siderophores as foreign compounds distinct from conventional peptides, and we provide evidence that this chemical variation influences the T cell response. One synthetic DDM recapitulated natural structures and potently stimulated T cells, making it suitable for patient studies of CD1a in infectious disease. DDM analogs differing in the stereochemistry of their butyrate or oxazoline moieties were not recognized by human T cells. Therefore, we conclude that T cells show precise specificity for both arms of the peptide, which are predicted to lie at the CD1a-T cell receptor interface.

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Section: Methodsmentioning

confidence: 99%

Synthesis of Dideoxymycobactin Antigens Presented by CD1a Reveals T Cell Fine Specificity for Natural Lipopeptide Structures

Young

Kasmar

Moraski

et al. 2009

Journal of Biological Chemistry

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“…The commercially unavailable starting aldehydes 21 and 23 were prepared according to the literature. 21,22) The trans-analog 13 was synthesized via the usual Honor-Emmons reaction. 19,20) (0.921 g, 2.28 mmol) in tetrahydrofuran (THF) (10 mL), Triton B (40% in methanol, 1.15 mL, 2.91 mmol) at −78°C under an argon atmosphere was added dropwise.…”

Section: Methodsmentioning

confidence: 99%

<i>cis</i>-Cinnamic Acid Selective Suppressors Distinct from Auxin Inhibitors

Okuda

Nishikawa

Fukuda

et al. 2014

CHEMICAL & PHARMACEUTICAL BULLETIN

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The activity of cis-cinnamic acid (cis-CA), one of the allelochemicals, in plants is very similar to that of indole-3-acetic acid (IAA), a natural auxin, and thus cis-CA has long been believed to be an analog of auxin. We have reported some structure-activity relationships studies by synthesizing over 250 cis-CA derivatives and estimating their inhibitory activities on root growth inhibition in lettuce. In this study, the compounds that showed low-or no-activity on root growth inhibition were recruited as candidates suppressors against cis-CA and/or auxin and tested for their activity. In the presence of cis-CA, lettuce root growth was inhibited; however, the addition of some cis-CA derivatives restored control-level root growth. Four compounds, (Z)-3-(4-isopropylphenyl)acrylic acid, (Z)-3-(3-butoxyphenyl)acrylic acid, (Z)-3-[3-(pentyloxy)phenyl]acrylic acid, and (Z)-3-(naphthalen-1-yl)acrylic acid were selected as candidates for a cis-CA selective suppressor they allowed the recovery of root growth from inhibition by cis-CA treatment without any effects on the IAA-induced effect or elongating activity by themselves. Three candidates significantly ameliorated the root shortening by the potent inhibitor derived from cis-CA. In brief, we have found some cis-CA selective suppressors which have never been reported from inactive cis-CA derivatives for root growth inhibition. cis-CA selective suppressors will play an important role in elucidating the mechanism of plant growth regulation.

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“…The resonance structures of carbanions are shown (Scheme 10). bond, which can be explained by structures b and c [70].…”

Section: (30)mentioning

confidence: 96%

Wittig and Wittig-Horner reactions under phase transfer catalysis conditions

et al. 2003

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Wittig and Wittig-Horner reactions are favorite tools in preparative organic chemistry. These ole nation methods enjoy widespread and recognition because of their simplicity, convenience, and e¯ciency. Phase transfer catalysis (PTC) is a very important method in synthetic organic chemistry having many advantages over conventional, homogenous reaction procedures. In this paper, we attempt to summarize the aspects concerning Wittig and Wittig-Horner reactions that take place under phase transfer catalysis conditions.

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The Utility of Phosphonate Carbanions in Olefin Synthesis

Cited by 1,354 publications

References 1 publication

Synthesis of Dideoxymycobactin Antigens Presented by CD1a Reveals T Cell Fine Specificity for Natural Lipopeptide Structures

Synthesis of Dideoxymycobactin Antigens Presented by CD1a Reveals T Cell Fine Specificity for Natural Lipopeptide Structures

<i>cis</i>-Cinnamic Acid Selective Suppressors Distinct from Auxin Inhibitors

Wittig and Wittig-Horner reactions under phase transfer catalysis conditions

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