Synthesis of Benzimidazoles through Palladium‐Catalyzed Amination of 2‐Iodobenzimines with Diaziridinone

Abstract

An efficient approach for the synthesis of benzimidazoles has been developed through the Pdcatalyzed amination of 2-iodobenzimines with diaziridinone. A wide range of 2-(hetero)aryl benzimidazloes are synthesized in good to excellent yields. The reactions likely involve C,C-palladacycles derived from 2iodobenzimines as the key intermediate, and the palladacycles reacted with diaziridinone to form benzimidazoles.

1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates

“…In this work, relatively inexpensive and safe FeCl 3 ·6H 2 O is shown to catalyze oxidative intramolecular CDC α to the 2° or 3° amines of N-substituted OPDs, to efficiently prepare many 1,2-disubstituted benzimidazoles (Scheme C). While synthetic methods for 1,2-disubstituted benzimidazoles construction have been developed ( 1A , 1B ), − the oxidative CDC methods leading to the construction of 1,2-disubstituted benzimidazoles are relatively underexplored. − These more recent methods involve Cu­(II)-mediated aerobic CDC to linear triazoles and tris­( o -phenylenediamine) macrocycles . The methods describe good yields only for select N , N ′-diarylmethyl-OPDs and do not investigate other OPD isomers or alkyl-OPD substrates.…”

Synthesis of 3,4-Fused Tricyclic Indoles through Cascade Carbopalladation and C–H Amination: Development and Total Synthesis of Rucaparib

“…C–H amination has also gained considerable interest and emerged as an innovative and powerful strategy for the formation of C–N bonds . In this context, N , N -di- tert -butyldiaziridinone represents a particularly intriguing C–H aminating reagent …”

“…A tentative mechanism is proposed for the tricyclic indole-forming reaction by using compound 1a as the model substrate (Scheme ). The reaction is initiated by the oxidative addition of 1a to Pd(0), affording aryl Pd­(II) species A . The subsequent intramolecular carbopalladation yields vinyl Pd­(II) species B .…”

Ionic‐Liquid‐Catalyzed Synthesis of Imines, Benzimidazoles, Benzothiazoles, Quinoxalines and Quinolines through C−N, C−S, and C−C Bond Formation

“…N ‐(4‐Chloro‐2‐iodophenyl)‐1‐phenylmethanimine (3 t) [18] Yield (324 mg, 95 % yield, brown oil), eluent: 5 % ethyl acetate/hexane; eluent: 2 % ethyl acetate/hexane; 1 H NMR (500 MHz, Chloroform‐ d ) δ 8.22 (s, 1H), 7.95–7.90 (m, 2H), 7.84 (d, J =2.3 Hz, 1H), 7.50–7.44 (m, 3H), 7.28 (dd, J =8.4, 2.3 Hz, 1H), 6.86 (d, J =8.4 Hz, 1H). 13 C NMR (125 MHz, Chloroform‐ d ) δ 161.26, 151.59, 138.28, 135.57, 132.01, 131.45, 129.39, 129.24, 128.92, 118.74, 95.36.…”