Herein we present a direct application of DABCO, an inexpensive and broadly accessible organic base, as a hydrogen atom transfer (HAT) abstractor in a photocatalytic strategy for aldehyde C–H activation. The acyl radicals generated in this step were arylated with aryl bromides through a well stablished nickel cross-coupling methodology, leading to a variety of interesting aryl ketones in good yields. We also performed computational calculations to shine light in the HAT step energetics and determined an optimized geometry for the transition state, showing that the hydrogen atom transfer between aldehydes and DABCO is a mildly endergonic, yet sufficiently fast step. The same calculations were performed with quinuclidine, for comparison of both catalysts and the differences are discussed.
在这里,我们提出了一种直接应用DABCO的方法,DABCO是一种廉价且广泛可获得的有机碱,作为光催化策略中醛的C-H活化的氢原子转移(HAT)抽取剂。在这一步骤中生成的酰基自由基通过一种成熟的镍交叉偶联方法与芳基溴化物芳基化,产生各种有趣的芳基酮,收率良好。我们还进行了计算计算,以阐明HAT步骤的能量学,并确定了过渡态的优化几何构型,表明醛和DABCO之间的氢原子转移是一个轻微的能量吸收过程,但足够快速。为了比较两种催化剂,我们还对喹啉进行了相同的计算,并讨论了它们之间的差异。