Benzylation of Acetylene. II. On the Structure and Oxidation of 3-Benzyl-3,4-diphenyl-1-Butyne

Ando, Teisuke; Tokura, Niichiro

doi:10.1246/bcsj.31.351

Cited by 5 publications

(2 citation statements)

References 9 publications

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“…Aware of previous solution-phase studies on the conversion of alkynes to α-ketocarboxylic acids and diketo derivatives, – we attempted the quantitative conversion of the TMS-protected aromatic acetylene into the corresponding α-ketocarboxylic acid. The use of NaIO 4 as an oxidizing agent should be avoided because of its general ability to cleave unsaturated C − C bonds.…”

Section: Resultsmentioning

confidence: 99%

“…The recently described Cu(I)-mediated cycloaddition of azides to alkynes, – displaying “click”properties adds yet another important transformation of the alkyne moiety to the chemist’s toolbox. The present reactions are known from solution-phase synthesis, – but no reports seem to exist on the solid-phase conversion of aromatic acetylenes to carboxylic acids, α-ketocarboxylic acids, or methyl ketones.…”

Section: Introductionmentioning

confidence: 99%

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Divergent Pathway for the Solid-Phase Conversion of Aromatic Acetylenes to Carboxylic Acids, α-Ketocarboxylic Acids, and Methyl Ketones

2008

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An efficient divergent pathway for the selective and quantitative solid-phase conversion of aromatic acetylenes to the corresponding carboxylic acids, alpha-keto-carboxylic acids, and methyl ketones is presented. A range of aromatic trimethylsilyl-protected acetylene building blocks was synthesized in excellent yields using a Sonogashira cross-coupling protocol and used in solid-phase synthesis on PEGA resin. Dependent on the selection of conditions, the same solid-supported alkyne could be quantitatively converted to an aromatic carboxylic acid, an aromatic alpha-ketocarboxylic acid, or an aromatic methyl ketone. The conversion to carboxylic acid involved an OsO4/NaIO4/HMTA-mediated oxidative cleavage of the silyl-deprotected alkyne to provide the aromatic carboxylate in excellent yield. The alpha-ketocarboxylic acids were obtained by direct treatment of the trimethylsilyl-protected alkyne with OsO4/NMO/HMTA, while the ketones were obtained by simple acid-mediated hydration of the alkyne using aqueous TFA. In general, all products were obtained in excellent purities, typically above 90%. In addition, it was shown that the alkyne-containing building blocks could easily be incorporated into resin-bound peptides and after chemoselective conversion of the alkyne the new functional groups could be used for further derivatization into peptidomimetic compounds.

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