Dearomative cycloadditions utilizing an organic photosensitizer: An alternative to iridium catalysis

Abstract

A highly efficient, cheap, and organic alternative to the commonly used iridium photosensitizer (Ir[dF(CF 3)ppy] 2 (dtbpy))PF 6 ([Ir−F]) is presented for visible-light energy transfer catalysis. The organic dye 2CzPN surpasses [Ir−F] in selectivity while at the same time being easily accessible in one step. The catalyst is recyclable and, due to its uncharged nature, soluble in nonpolar solvents such as toluene. Furthermore, the scope of molecular scaffolds that are compatible substrates for visible-light catalyzed dearomative cycloadditions is expanded.

Spirocyclizative Remote Arylcarboxylation of Non-Activated Arenes with CO2 via Visible-Light-Induced Reductive Dearomatization

“…We suspected the product might be labile, resulting in a relatively lower yield. Gratifyingly, substrates bearing a series of substituents on the indole ring or the aryl bromide ring could be converted into the corresponding products in moderate yields (56)(57)(58)(59)(60)(61)(62)(63)(64)(65). It should be mentioned, generally about 5% of arylcarboxylation of indole's C2-C3 double bond and/or about 5% of direct debromination side products were also observed.…”

“…In recent years, visible-light photoredox catalysis [35][36][37][38][39][40][41][42][43][44] has emerged as a promising strategy for developing mild protocols for dearomatization, [45][46][47][48][49][50][51][52][53][54][55][56][57][58] including several significant protocols for the dearomatization of nonactivated arenes, [59][60][61][62][63][64][65][66][67][68][69][70][71][72][73] such as dearomative cycloadditions mainly from the groups of Sarlah and Bach, [59][60][61][62] and oxidative dearomatization. [63][64][65] A distinct redox-neutral hydroalkylative dearomatization of naphthalene derivatives was also reported by the group of Zhang, Mei and You.…”

Spirocyclizative Remote Arylcarboxylation of Nonactivated Arenes with CO 2 via Visible-Light-Induced Reductive Dearomatization

“…We suspected the product might be labile, resulting in a relatively lower yield. Gratifyingly, substrates bearing a series of substituents on the indole ring or the aryl bromide ring could be converted into the corresponding products in moderate yields (56)(57)(58)(59)(60)(61)(62)(63)(64)(65). It should be mentioned that generally about 5% product of arylcarboxylation of indole's C2-C3 double bond, and side products from debromination (about 5%) as well as hydroarylation of the 2-phenyl group (generally less than 5%) were also observed.…”

“…In recent years, visible-light photoredox catalysis [36][37][38][39][40][41][42][43][44][45] has emerged as a promising strategy for developing mild protocols for dearomatization, [46][47][48][49][50][51][52][53][54][55][56][57][58][59] including several significant protocols for the dearomatization of nonactivated arenes, [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74] such as dearomative cycloadditions that were mainly from the groups of Sarlah and Bach, [60][61][62][63] and oxidative dearomatization. [64][65][66] A distinct redox-neutral hydroalkylative dearomatization of naphthalene derivatives was also reported by the group of Zhang, Mei and You.…”