Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China.
Angew Chem Int Ed Engl. 2020 Jan 7;59(2):653-657. doi: 10.1002/anie.201909557. Epub 2019 Nov 18.
Palladium-catalyzed alkene-directed cross-coupling of aryl iodide with another aryl halide through C-H arylation opens a unique avenue for unsymmetrical biaryl-derived molecules. However, homo-coupling of aryl iodides often erodes the overall synthetic efficiency. Reported herein is a highly chemoselective Pd -catalyzed alkyne-directed cross-coupling of aryl iodides with bromophenols, which was subsequently followed by phenol dearomatization to furnish a very attractive [2+2+1] spiroannulation. Notably, possible homo-coupling of aryl iodides was not observed at all. Mechanistic studies indicated that a five-membered aryl/vinyl palladacycle most likely accounts for promoting the key step of biaryl cross-coupling.
钯催化的烯烃导向的芳基碘与另一个芳基卤化物的交叉偶联通过 C-H 芳基化开辟了一个独特的途径，用于不对称联芳基衍生的分子。然而，芳基碘的同偶联常常降低了整体的合成效率。本文报道了一种高化学选择性的钯催化的炔烃导向的芳基碘与溴苯酚的交叉偶联，随后进行苯酚去芳构化，以提供一种非常有吸引力的[2+2+1]螺环化。值得注意的是，根本没有观察到芳基碘的可能同偶联。机理研究表明，五元芳基/乙烯基钯环合物很可能是促进关键的联芳基交叉偶联步骤的原因。
