Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, Paris, France.
PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, Paris, France.
Nat Chem. 2019 Sep;11(9):797-805. doi: 10.1038/s41557-019-0295-9. Epub 2019 Aug 5.
The well-established oxidative addition-reductive elimination pathway is the most followed one in transition metal-catalysed cross-coupling reactions. While readily occurring with a series of transition metals, gold(I) complexes have shown some reluctance to undergo oxidative addition unless special sets of ligands on gold(I), reagents or reaction conditions are used. Here we show that under visible-light irradiation, an iridium photocatalyst triggers-via triplet sensitization-the oxidative addition of an alkynyl iodide onto a vinylgold(I) intermediate to deliver C(sp)-C(sp) coupling products after reductive elimination. Mechanistic and modelling studies support that an energy-transfer event takes place, rather than a redox pathway. This particular mode of activation in gold homogenous catalysis was applied in several dual catalytic processes. Alkynylbenzofuran derivatives were obtained from o-alkynylphenols and iodoalkynes in the presence of catalytic gold(I) and iridium(III) complexes under blue light-emitting diode irradiation.
在过渡金属催化的交叉偶联反应中，被广泛认可的氧化加成-还原消除途径是最常用的途径。尽管一系列过渡金属很容易发生氧化加成反应，但金（I）配合物除非使用特殊的金（I）配体、试剂或反应条件，否则很难发生氧化加成反应。在这里，我们表明在可见光照射下，铱光催化剂通过三重态敏化触发炔基碘化物与乙烯基金（I）中间体的氧化加成，在还原消除后生成 C(sp)-C(sp) 偶联产物。机理和模型研究支持发生了能量转移事件，而不是氧化还原途径。这种在金均相催化中的特殊激活模式在几种双催化过程中得到了应用。在蓝光发光二极管照射下，在催化金（I）和铱（III）配合物的存在下，邻炔基苯酚和碘炔反应得到炔基苯并呋喃衍生物。
