Iodine-catalyzed $$\hbox {sp}^{3}$$ sp 3 C–H bond activation by selenium dioxide: synthesis of diindolylmethanes and di(3-indolyl)selanides

Abstract

An efficient reaction protocol was developed for the synthesis of several diindolylmethane derivatives via the [Formula: see text] C-H bond activation of aryl methyl ketones by [Formula: see text] and indoles in the presence of catalytic amounts of [Formula: see text] at 80 [Formula: see text] using dioxane as solvent. Unexpectedly, an interesting class of di(3-indolyl)selenide compounds was isolated when the reaction was carried out at room temperature.

A Study on the Reactions of SeO2 with Pyrroles and N‐Substituted Indoles in Non‐Anhydrous Ethanol under Non‐Inert Atmosphere

“…Table denotes the reaction outcomes of various indoles with 2 . N‐benzyl ( 1 b ) and N‐isopropyl indoles ( 1 c ) underwent smooth reactions under the optimized conditions to give the corresponding 3,3′‐diindolyl selenides 3 (entries 2 and 3 respectively). It is noteworthy that electronic withdrawing group protected N‐benzoyl indole did not undergo any reaction even at elevated temperature keeping other reaction conditions identical (entry 4), probably due to non‐availability of unpaired electrons on nitrogen.…”

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

“…The work of Abele in 2004 involved refluxing SeO 2 with N -unprotected indole in benzene which resulted in low yields of the products 134 ( Scheme 18a ) [ 44 ]. Using different N -protected substituted indoles 135 , Naidu observed improved yields of 136 when catalytic oxidant I 2 was added in 1,4-dioxane as solvent ( Scheme 18b ) [ 96 ]. Using aerial oxygen as the oxidant, Yang used Se 0 in the presence of stoichiometric KI and catalytic amounts of Fe II for the synthesis of similar bis(indol-3-yl)selanes ( Scheme 18c ) [ 83 ].…”

“…Bis(indol-3-yl)selanes possess antioxidant properties. Pioneered by Wilshire [94], their syntheses were studied by Abele [95], Naidu [96], Yang [83], Thurow [97], and Talukdar [98]. The work of Abele in 2004 involved refluxing SeO 2 with N-unprotected indole in benzene which resulted in low yields of the products 134 (Scheme 18a) [44].…”