Photoinduced Intramolecular Cyclization of o-Ethenylaryl Isocyanides with Organic Disulfides Mediated by Diphenyl Ditelluride

Abstract

Photoinduced reaction of o-ethenylaryl isocyanides with organic disulfides in the presence of diphenyl ditellurides affords the corresponding bisthiolated indole derivatives via a radical cyclization process. The cyclization can proceed at room temperature upon visible-light irradiation and exhibits good tolerance to functional groups. Several organic disulfides also can be employed for this cyclization, and the corresponding bisthiolated indole derivatives are obtained selectively. In addition, the photoinduced reaction of o-ethenylaryl isocyanides with bis(2-aminophenyl) disulfide affords tetracyclic compounds in one portion.

Highly selective introduction of heteroatom groups to isocyanides and its application to electrocyclic reactions

“…At first, we attempted radical cyclization reaction of o-alkenylaryl isocyanides by using the (PhS) 2 -(PhSe) 2 mixed system, but the reaction provided a complex mixture including 1,1-thioselenation product of isocyanide unit, cyclic thioselenation product, and cyclic bisthiolation product (Scheme 2). In contrast, the photoinduced reaction of o-alkenylaryl isocyanides by using the (PhS) 2 -(PhTe) 2 mixed system led to the formation of cyclic bisthiolation product selectively [9]. Compared with carbon-selenium bonds, carbon-tellurium bonds are unstable under photoirradiation conditions, and are replaced with stable carbon-sulfur bonds.…”

“…785-799, 2013 792 Fig. 2 ORTEP diagram of (12H-Benzo [4,5]thiazolo[2,3-b]quinazolin-12-yl)acetonitrile [9].…”

Iodine-catalysed versatile sulfenylation of indoles with thiophenols: controllable synthesis of mono- and bis-arylthioindoles

“…6,136.6,131.7,130.8,128.8,127.5,123.3,121.1,119.5,118.4,111.8,102.3;HRMS (ESI) Calcd. for C 20 H 12 Br 2 NS 2 ([M-H] -) 489.8757, Found 489.8750.…”

“…3 On account of the intriguing synthetic value and varying pronounced bioactivities of these compounds, the synthetic repertoire has currently enjoyed a resurgence of interest after the initial studies in 1980s, 4 and resulted in the development of two major synthetic strategies. The first route is achieved by cyclization reactions of 2-alkynylanilines, 5 o-ethenylaryl isocyanides, 6 2-(gem-dibromo(chloro)vinyl) anilines 7 or phenylhydrazine hydrochloride, 8 whereas the other method involves the direct sulfenylation of a pre-existing indole ring owing to its nucleophilic nature, 9-16 using arylsulfenyl halides, 4a,17b,c diaryl disulfides, 9 aryl-N-thioimides, 10 aryl thiols, 11 arylsulfonyl chlorides, 12 sulfonyl hydrazides, 13 quinone mono-O,S-acetals, 14 arylsulfonium salts 15 and sulfinic acids 16 as sources of the sulfenylating agents. Nevertheless, many of these sulfurtransfer reagents are either difficult to prepare or air and moisture sensitive.…”

Mn(III)‐Mediated Regioselective 6‐endo‐trig Radical Cyclization of o‐Vinylaryl Isocyanides to Access 2‐Functionalized Quinolines

“…For example, Ogawa and coworkers synthesized bisthiolated indoles via 5-exo-trig radical cyclization from o-ethenyl arylisocyanides with disulfide reagents. [13] Afterwards, Studer et al constructed mono-and bis-trifluoromethylated indoles by adjusting the substituents on oalkenyl groups from o-alkenyl arylisocyanides and Togni's reagent. [14] Furthermore, the photoredox synthesis of 2-phosphinoylindoles though 5-exo-trig radical annulation/hydrogen atom transfer (HAT) process was disclosed by Yang's group.…”