Manganese(iii)-promoted tandem phosphinoylation/cyclization of 2-arylindoles/2-arylbenzimidazoles with disubstituted phosphine oxides

Abstract

<p>A simple and practical manganese(<sc>iii</sc>)-promoted tandem phosphinoylation/cyclization of 2-arylindoles/2-arylbenzimidazoles with disubstituted phosphine oxides was developed.</p>

Electrochemical Tri‐ and Difluoromethylation‐Triggered Cyclization Accompanied by the Oxidative Cleavage of Indole Derivatives

“…For example, the challenging task of constructing functionalized oxindoles has been accomplished by the groups of Lei, [7d] Zeng, [7e] Mo, [7g] and other groups (Scheme 1 a). Also, addition of various carbon or phosphorous [8] radicals, including fluorinated ones, [8c] to the same 2‐Ph indoles N‐substituted by an acryloyl group is known to be promoted by electrochemistry, [8a] visible light, [8b,c] or stoichiometric oxidants [8d, e] . The difference with the present work is that the oxidative cleavage of the indole does not occurs in these previous reports.…”

Transition Metal‐Free Synthesis of Sulfonyl‐ and Bromo‐Substituted Indolo[2,1‐α]isoquinoline Derivatives through Electrochemical Radical Cascade Cyclization

“…In 2020, Lei and co‐ workers reported a Mn‐catalyzed electrochemical radical cascade cyclization reaction that utilized alkylboronic acids as alkyl radical precursors, leading to a series of alkylated indolo[2,1‐α]isoquinolines as products [9] . In addition, the synthesis of perfluoroalkyl‐, phosphoryl‐, and selenyl‐substituted indolo[2,1‐α]isoquinoline derivatives from 2‐aryl‐ N ‐acryloyl indoles was further developed through visible light‐, manganese‐, and iron‐promoted synthetic pathways, respectively [10–12] …”

“…Replacing the Pt anode with a graphite rod led to a dramatic drop in the yield of 3 a (entry 6). Moreover, other solvent systems were explored but provided no improvement over THF/H 2 O (entries [7][8][9][10][11]. Notably, the yield of 3 a was slightly reduced when 2.0 equiv.…”

Synthesis of Indolo[2,1‐a]isoquinolin‐6(5H)‐Ones Derivatives via Fe(OTf)3‐Promoted Tandem Selenylation/Cyclization of 2‐Arylindoles

“…Lei's group reported a Mn‐catalyzed electrochemical radical cascade cyclization reaction to indolo[2,1‐a]isoquinoline derivatives from 2‐arylindoles and boronic acids [9] . Very recently, Li's group reported Mn‐promoted tandem phosphinoylation /cyclization of 2‐arylindoles to phosphoryl‐substituted indolo[2,1‐ a ]isoquinolin‐6(5 H )‐ones [10] . However, a method for introducing a selenyl group into the unique indolo[2,1‐a]isoquinoline core has not been studied.…”