Browsing by Subject "Alkynes"

Now showing 1 - 2 of 2
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    Highly selective electrochemical hydrogenation of alkynes: Rapid construction of mechanochromic materials
    (American Association for the Advancement of Science, 2019-05-24) Li, Bijin; Ge, Haibo; Chemistry and Chemical Biology, School of Science
    Electrochemical hydrogenation has emerged as an environmentally benign and operationally simple alternative to traditional catalytic reduction of organic compounds. Here, we have disclosed for the first time the electrochemical hydrogenation of alkynes to a library of synthetically important Z-alkenes under mild conditions with great selectivity and efficiency. The deuterium and control experiments of electrochemical hydrogenation suggest that the hydrogen source comes from the solvent, supporting electrolyte, and base. The scanning electron microscopy and x-ray diffraction experiments demonstrate that palladium nanoparticles generated in the electrochemical reaction act as a chemisorbed hydrogen carrier. Moreover, complete reduction of alkynes to saturated alkanes can be achieved through slightly modified conditions. Furthermore, a series of novel mechanofluorochromic materials have been efficiently constructed with this protocol that showed blue-shifted mechanochromism. This discovery represents the first example of cis-olefins-based organic mechanochromic materials.
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    Photoinduced oxidative cyclopropanation of ene-ynamides: synthesis of 3-aza[n.1.0]bicycles via vinyl radicals
    (Royal Society of Chemistry, 2021-05) Deng, Yongming; Zhang, Jason; Bankhead, Bradley; Markham, Jonathan P.; Zeller, Matthias; Chemistry and Chemical Biology, School of Science
    The first photoinduced synthesis of polyfunctionalized 3-aza[n.1.0]bicycles from readily available ene-ynamides and 2,6-lutidine N-oxide using an organic acridinium photocatalyst is reported. Applying a photocatalytic strategy to the reactive distonic cation vinyl radical intermediate from ynamide, a series of bio-valuable 3-azabicycles, including diverse 3-azabicyclio[4.1.0]heptanes and 3-azabicyclo[5.1.0]octanes that are challenging to accomplish using traditional methods, have been successfully synthesized in good to high yields under mild and metal-free conditions. Mechanistic studies are consistent with the photocatalyzed single-electron oxidation of ene-ynamide and the intermediacy of a putative cationic vinyl radical in this transformation. Importantly, this strategy provides new access to the development of photocatalytic vinyl radical cascades for the synthesis of structurally sophisticated substrates.