Visible-Light-Mediated Three-Component Decarboxylative Coupling Reactions for the Synthesis of 4‑Alkylpyridines

4-Alkylation of pyridines has been achieved by a photocatalyzed three-component reaction of an olefin, an aryloxyacetic acid, and cyanopyridine using Ir[dF(CF3)ppy]2(dtbbpy)PF6 as a photocatalyst. In this way, a new type of 4-alkylpyridines bearing aryl and aryloxy substituents on the phenyl was accessed with potential pharmaceutical value. In addition to mild reaction conditions, the method has several other advantages, including a multicomponent one-pot protocol, good functional group tolerance, and easy amplification of the reaction scale. The reaction mechanism has been clarified by control experiments and computation of the reaction energy profile.以Ir[dF(CF3)ppy]2(dtbbpy)PF6为光催化剂，通过烯烃、芳氧基乙酸与氰基吡啶参与的光催化三组分反应，可实现吡啶的4位烷基化。通过该策略可合成一类在苯环上连有芳基与芳氧基取代基的新型4-烷基吡啶类化合物，此类化合物具备潜在药用价值。该方法除反应条件温和外，还具备诸多优势：包括多组分一锅法合成策略、优异的官能团耐受性，以及反应规模易于放大。通过对照实验与反应能量轮廓计算，该反应的机理已得到阐明。