The mechanisms for new palladium‐catalyzed divergent reactions of triazolopyridines were investigated by means of DFT calculations. Previously, it was observed experimentally that cross‐coupling at the C7‐position of triazolopyridines occurred when a strong base was used, whereas the reaction could be diverted to the C3‐position if a weak base was employed. Calculations suggest that a strong base, such as tert‐butoxide, can easily deprotonate C7−H, independent of the palladium metal, and deliver the preactivated substrate to palladium, which can reductively eliminate the final product. Without a strong base, the palladium(II) center reacts with the ring‐opened diazo imine isomer of triazolopyridine to initially form a palladium(II)–carbene intermediate, which undergoes migratory insertion followed by β‐hydride elimination to afford a 1,1‐disubstituted alkene.

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钯催化的三唑并吡啶的发散丙烯酸化：计算研究

通过DFT计算研究了新的钯催化的三唑并吡啶的发散反应的机理。以前，通过实验观察到，当使用强碱时，三唑并吡啶的C7位发生交叉偶联，而如果使用弱碱，则该反应可转移至C3位。计算结果表明，有很强的基础，例如叔叔丁醇盐可以很容易地使C7–H质子化，而与钯金属无关，并将预活化的底物传递到钯上，从而可以还原性地消除最终产物。在没有强碱的情况下，钯（II）中心与三唑并吡啶的开环重氮亚胺异构体反应，最初形成钯（II）-卡宾中间体，该中间体经过迁移插入，然后经β-氢化物消除，得到1,1。 -二取代的烯烃。