Palladium-catalyzed direct desulfitative C2 arylations of 3-halo-N-protected indoles using (hetero)arenesulfonyl chlorides

Abstract

. Palladium-catalyzed direct desulfitative C2 arylations of 3-halo-: N -protected indoles using (hetero)arenesulfonyl chlorides. Organic and Biomolecular Chemistry, Royal Society of Chemistry, 2016, 14 (21) The direct arylation of N-protected 3-haloindole derivatives with benzenesulfonyl chlorides as coupling partners using 5 mol% of bis(acetonitrile)dichloropalladium(II) catalyst and lithium carbonate as base in 1,4-dioxane was investigated. We demonstrated that both iodo and chloro substituents at indolyl C3 position act as temporary blocking groups to allow the formation of 2-arylindoles through a direct desulfitative arylation, followed by in-situ dehalogenation. While, from 3-bromoindole derivatives, 2-aryl-3-bromoindoles were obtained without debromination, and could be converted into 2,3-diarylindoles through a second palladium coupling. which are both of interest as potential intermediates in the synthesis of bioactive molecules.

Visible‐Light‐Driven Sulfonylation/Cyclization to Access Sulfonylated Benzo[4,5]imidazo[2,1‐a]isoquinolin‐6(5H)‐ones

“…In photoredox transformations containing sulfonyl chlorides, a major process is to develop C−C bond after the loss of SO 2 , the methods on the formation of C−S bond are very rare [22] . Sulfone functional groups with great synthetic potential are widely used in the fields of agrochemicals and natural product synthesis, and many sulfonyl‐functionalized compounds have excellent biological properties [23–33] . Herein, we reported a new and efficient visible‐light‐induced sulfonylation/cyclization reaction that used the sulfonyl chloride as the sulfonylation reagent and oxidant to promote the reaction, leading to a series of sulfonylated benzimidazo[2,1‐ a ]isoquinolin‐6(5 H )‐ones under mild reaction conditions (Scheme 1,d).…”