Copper‐Catalyzed Aerobic Cross‐Dehydrogenative Coupling of β‐Oxime Ether Furan with Indole

Heterobiaryls serve as relevant structural motifs in many fields of high applicative importance such as drugs, agrochemicals, organic functional materials etc. Cross‐dehydrogenative coupling involving direct oxidation of two C−H bonds to construct a C−C bond is actively being pursued as a more benign and ‘greener’ alternative for synthesizing heterobiaryls. Herein, we report a Cu(I)‐catalyzed cross‐dehydrogenative coupling of indoles and furans, two of the most important aromatic heterocycles using air as the terminal oxidant. The reaction proceeds with regio‐ and chemoselectivity to give the cross‐coupled products in good to excellent yields generally. A broad substrate scope with respect to both the coupling partners has been demonstrated to prove the generality of this reaction. This represents the hitherto unexplored cross‐dehydrogenative coupling methodology to obtain an indole‐furan biaryl motif. Furan and Indole represent two of the most versatile heterocycles in organic chemistry. Herein, we report the first cross‐dehydrogenative coupling of these two heterocycles catalyzed by copper in combination with aerial oxygen. Additionally, we also demonstrate a lesser known activating group effect of oxime ether substituent in oxidative coupling. The reaction has broad substrate scope and exhibits excellent chemoselectivity.