Photocatalytic Redox-Neutral Approach to Diarylmethanes

Abstract

We report a visible-light induced redox-neutral decarboxylative cross coupling reaction of indole-3-acetic acid NHPI esters with indoles using a Ru photosensitizer to deliver a wide range of symmetrical and unsymmetrical 3,3′-bisindolylmethane derivatives. Furthermore, the reaction is readily adapted to the preparation of a wide variety of diarylmethane derivatives.

One-Pot Sequential Synthesis of 3,3′- or 2,3′-Bis(indolyl)methanes by Using 1,3-Dithiane as the Methylene Source

“…HRMS (ESI-TOF): calcd for C 17 H 13 FN 2 Na + [M + Na] + 287.0955, found 287.0954. All spectroscopic data are in accordance with literature …”

“…In 2013, the Tang group demonstrated a platinum-catalyzed tandem indole annulation/arylation cascade for various 2,3′-BIMs (Scheme a) . More recently, the Huo group reported a visible-light-induced redox-neutral decarboxylative coupling reaction of indole-3-acetic acid NHPI esters with indoles for symmetrical and unsymmetrical BIMs (Scheme b) . However, these substrates are not commercially available and some have limited bench work.…”

K2S2O8-glucose mediated oxidative coupling of alcohols with indoles for synthesis of bis(indolyl)methanes in water

“…) is a commercially available oxidizing agent and has been extensively involved in a wide array of oxidative organic transformations and oxidation of environmental contaminants. [30][31][32][33][34][35][36][37][38][39] In the literature, the use of K 2 S 2 O 8 -Brønsted ionic liquid ([Hmim]-CH 3 SO 3 ) 40 and K 2 S 2 O 8 -activated charcoal 41 for specific oxidation of alcohols to carbonyl analogues has been reported. To the best of our knowledge, we have found only one report where K 2 S 2 O 8 -glucose has been used for synthesis of diverse heterocycles.…”

Palladium-Catalyzed Three-Component Regioselective Dehydrogenative Coupling of Indoles, 2-Methylbut-2-ene, and Carboxylic Acids

“…As depicted in Scheme , a series of N–H indoles bearing various substitutes, such as halides, cyano, formyl, ester, and nitro, were compatible with this mild catalytic system, delivering the desired products in 39–77% yields ( 6gg – 6oo ). It is worth noting that pharmaceutical molecule derivatives 1pp and 1qq also afforded the corresponding products in good yields ( 6pp and 6qq ). , Notably, instead of indole with 2-methylindole, 7-azaindole, and pyrrole, the three-component dehydrogenative cascade couplings could not proceed. The structure of product 6nn was confirmed by single-crystal X-ray diffraction.…”

“…It is worth noting that pharmaceutical molecule derivatives 1pp and 1qq also afforded the corresponding products in good yields (6pp and 6qq). 21,22 Notably, instead of indole with 2-methylindole, 7-azaindole, and pyrrole, the three-component dehydrogenative cascade couplings could not proceed. The structure of product 6nn was confirmed by single-crystal X-ray diffraction.…”