An efficient metal-free protocol has been developed for the sp³ C–H bond oxidation of 2-methylquinolines in the presence of PIDA under microwave irradiation, providing 2-quinolinecarboxaldehydes with moderate to high yields and excellent selectivities. A wide range of 2-quinolinecarboxaldehydes with different functional groups have been synthesized. A tentative mechanism has been presented to explain this highly selective oxidation process.

中文翻译：

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微波辐射下PIDA对2-甲基喹啉的无金属C（sp3）–H氧化

在微波辐射下，在PIDA存在下，已开发出一种有效的无金属方案，用于2-甲基喹啉的sp ³ C–H键氧化，可提供中等至高收率和优异的选择性的2-喹啉甲醛。已经合成了范围广泛的具有不同官能团的2-喹啉甲醛。已经提出了一种尝试机制来解释这种高度选择性的氧化过程。