I<sub>2</sub>-Mediated Oxidative C–N Bond Formation for Metal-Free One-Pot Synthesis of Di-, Tri-, and Tetrasubstituted Pyrazoles from α,β-Unsaturated Aldehydes/Ketones and Hydrazines
An I2-mediated metal-free oxidative C–N bond formation methodology has been established for the regioselective pyrazole synthesis. This practical and eco-friendly one-pot protocol requires no isolation of the less stable intermediates hydrazones and provides a facile access to a variety of di-, tri-, and tetrasubstituted (aryl, alkyl, and/or vinyl) pyrazoles from readily available α,β-unsaturated aldehydes/ketones
I 2介导的无金属氧化C–N键形成方法已建立用于区域选择性吡唑合成。这种实用且环保的一锅操作方案无需分离不稳定程度较高的中间体s,并易于从容易获得的多种二,三和四取代(芳基,烷基和/或乙烯基)吡唑中分离α,β-不饱和醛/酮和肼盐。
Iridium-Catalyzed Synthesis of Substituted Indanones from Aromatic Carboxylates and Unsaturated Ketones
作者:Guodong Zhang、Zhiyong Hu、Giulia Bertoli、Lukas J. Gooßen
DOI:10.1021/acscatal.9b02536
日期:2019.9.6
A catalytic annulation is presented that provides straightforward, modular synthetic access to 3-substituted indanones from benzoic acids and α,β-unsaturated ketones. It is catalyzed by a bimetallic Ir/In system and proceeds via hydroarylation followed by Claisen condensation and optional retro-Claisen deacylation. The annulation may be combined into a one-pot procedure with the synthesis of the unsaturated
Re catalysis in one‐pot reactions: An atom‐economical, one‐pot strategy that involves alkyne deprotonation and a subsequent rhenium(V)‐catalysed Meyer–Schuster rearrangement of the alkynol to provide α,ß‐unsaturated enones in high yield has been developed (see scheme). Subsequent in situ hydride reduction or Diels–Alder reaction of the enones provided products in good‐to‐high overall yields.