Harnessing Vinyl Acetate as an Acetylene Equivalent in Redox-Neutral Cp*Co(III)-Catalyzed C–H Activation/Annulation for the Synthesis of Isoquinolones and Pyridones

We have developed Cp*Co­(III)-catalyzed redox-neutral
synthesis
of 3,4-unsubstituted isoquinoline 1­(2H)-ones at ambient
temperature using N-chloroamides as a starting material.
The reaction utilizes vinyl acetate as an inexpensive and benign acetylene
surrogate. The N–Cl bond of the N-chlorobenzamides
plays the role of an internal oxidant and hence precludes the need
for an external oxidant. The reaction works with a wide range of substrates
having various functional groups and a substrate containing a heterocyclic
ring. Notably, the reaction is extended to the N-chloroacrylamides
in which vinylic C–H activation occurs to furnish the 2-pyridone
derivatives. Preliminary mechanistic studies were also conducted to
shed light on the mechanism of this reaction.

本研究团队已成功开发出一种在室温下，以N-氯代酰胺为起始原料，由Cp*Co(III)催化的氧化还原中性合成3,4-未取代异喹啉-1-(2H)-酮的方法。该反应采用乙烯基乙酸酯作为廉价的、环境友好的乙炔替代品。N-氯代苯甲酰胺中的N-Cl键充当内部氧化剂的角色，从而消除了对外部氧化剂的依赖。此反应适用于多种具有不同官能团以及含有杂环环状结构的底物。尤为引人注目的是，该反应还被扩展至N-氯代丙烯酰胺，其中乙烯基C-H的活化作用生成了2-吡啶酮衍生物。此外，为了阐明该反应的机理，我们还进行了初步的机理研究。