Highly regioselective gold-catalyzed formal hydration of propargylic <i>gem</i>-difluorides
作者:Jean-Denys Hamel、Tatsuru Hayashi、Mélissa Cloutier、Paul R. Savoie、Olivier Thibeault、Meggan Beaudoin、Jean-François Paquin
DOI:10.1039/c7ob02406a
日期:——
Herein, we report a highlyregioselective gold-catalyzed formal hydration of propargylic gem-difluorides. Not only does this transformation provide access to versatile fluorinated building blocks that were difficult or hardly possible to access beforehand, but it also represents a rare case of a highlyregioselective gold-catalyzed hydroalkoxylation of internal alkynes and puts forward the utility
We report that aromatic propargylation is achievable with secondary propargylic fluorides, thus affording 1-alkyl-1-aryl-2-alkynes. In the present case, hydrogen bonding is responsible for the activation of the C–F bond. A large excess of arene nucleophile is shown to be necessary to achieve good yields.
Versatile synthesis of α, β-acetylenic ketones by oxidative nucleophilic addition of vanadium acetylides
作者:Toshikazu Hirao、Daisuke Misu、Toshio Agawa
DOI:10.1016/s0040-4039(00)84141-6
日期:1986.1
Treatment of aldehydes with vanadium acetylides generated from equimolar amounts of vanadium trichloride and acetylenic Grignard or lithium compounds gave α,β-acetylenicketones via oxidative nucleophilic addition.
Alkynyl<i>N</i>-Nosylhydrazones: Easy Decomposition to Alknynl Diazomethanes and Application in Allene Synthesis
作者:Yang Yang、Zhaohong Liu、Alessio Porta、Giuseppe Zanoni、Xihe Bi
DOI:10.1002/chem.201701462
日期:2017.7.6
reaction with boronic acids under metal-free conditions is reported, giving rise to a wide array of di- and trisubstituted allenes. Preliminary mechanistic investigations demonstrated that γ-protodeboration of propargyl boric acid was responsible for the initial allene formation. This methodology based on the nosyl group allows for novel transformations that involve an alkynylcarbene transient species
Selective Oxidation of Unsaturated Alcohols Catalyzed by Sodium Nitrite and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone with Molecular Oxygen under Mild Conditions
practical process for the oxidation of alcohols to the corresponding carbonyl compounds by using a low catalytic amount of DDQ, NaNO2 as a cocatalyst, and molecularoxygen as terminal oxidant. Nitric oxide generated in situ by NaNO2 in the presence of AcOH is essential for the realization of the catalytic cycle at room temperature. The practical utility of this catalytic process has been demonstrated