Mechanosynthesis of Odd‐Numbered Tetraaryl[
<i>n</i>
]cumulenes
作者:Karen J. Ardila‐Fierro、Carsten Bolm、José G. Hernández
DOI:10.1002/anie.201905670
日期:2019.9.9
A mechanochemical synthesis of one‐dimensional carbon allotrope carbyne model compounds, namely tetraaryl[n]cumulenes (n=3, 5) was realized. Central for the mechanosynthesis of the cumulenic carbon nanostructures were the development of a mechanochemical Favorskii alkynylation‐type reaction and the implementation of a solvent‐free, acid‐free reductive elimination with tin(II) chloride by ball milling
实现了一维碳同素异形体碳炔模型化合物,即四芳基[ n ]累积烯(n =3, 5)的机械化学合成。积碳碳纳米结构机械合成的核心是机械化学 Favorskii 炔基化反应的发展,以及通过球磨实现无溶剂、无酸的氯化锡 (II) 还原消除。
Organocatalytic Enantioselective Vinylogous Pinacol Rearrangement Enabled by Chiral Ion Pairing
作者:Hua Wu、Qian Wang、Jieping Zhu
DOI:10.1002/anie.201609911
日期:2016.12.5
An enantioselective pinacol rearrangement of functionalized (E)‐2‐butene‐1,4‐diols was developed. In the presence of a catalytic amount of a chiral BINOL‐derived N‐triflyl phosphoramide, these 1,4‐diols rearranged to β,γ‐unsaturated ketones in excellent yields and enantioselectivities. The formation of a chiral ion pair between the intermediary allylic cation and the chiral phosphoramide anion was
Acid-Catalyzed Domino Reactions of Tetraarylbut-2-yne-1,4-diols. Synthesis of Conjugated Indenes and Inden-2-ones
作者:Céu M. Sousa、Jerome Berthet、Stephanie Delbaere、Paulo J. Coelho
DOI:10.1021/jo500907z
日期:2014.6.20
The reaction of tetraarylbut-2-yne-1,4-diols with electron-rich aromatic compounds at room temperature, under p-TsOH catalysis, affords substituted polycyclic aromatic indene derivatives through a domino reaction involving the formation of a cationic allenylium intermediate. This species can undergo a series of competitive intramolecular cascade reactions, leading to a conjugated inden-2-one. This
Synthesis of 1-Vinylidene-naphthofurans: A Thermally Reversible Photochromic System That Colors Only When Adsorbed on Silica Gel
作者:Céu M. Sousa、Jerome Berthet、Stephanie Delbaere、Paulo J. Coelho
DOI:10.1021/jo400710r
日期:2013.7.19
A set of new 1-vinylidene-1,2-dihydro-naphtho[2,1-b]furans were unexpectedly obtained in the reaction of 2-naphthol with readily available 1,1,4,4-tetraarylbut-2-yne-1,4-diols. Surprisingly, when adsorbed in silica gel, these compounds exhibit photochromism at room temperature, whereas not in solution and in the solid state. UV or sunlight irradiation leads, in a few seconds, to the formation of intense pink/violet to green colors that bleach completely in a few minutes in the dark. These new compounds also exhibit reversible acidochromic properties in solution: addition of TFA leads to the opening of the furan ring and addition of a proton to the allene function, leading to a conjugated and violet tertiary carbocation that returned immediately to the uncolored allenic structure upon addition of a weak base.