Gold(I)-Catalyzed and Iodonium Monochloride-Mediated Carboannulations of Indole/Benzofuran-Based Acetylenic Substrates: Easy Access to δ-Carbolines and Benzofuro[3,2-b]pyridines

IF 3.6 2区化学 Q1 CHEMISTRY, ORGANIC

Journal of Organic Chemistry Pub Date : 2025-06-11 DOI:10.1021/acs.joc.5c00267

Sarat Chatterjee, Aparajita Mandal, Raghunath Das, Debasmita Mondal, Susmita Pratihar and Chinmay Chowdhury*,

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Abstract

Au(I)-catalyzed tandem cyclization of indole-/benzofuran-based N-propargylsulphonamides 3 and 4 led to the formation of dihydro δ-carboline and benzofuro[3,2-b]pyridine intermediates, which underwent a base (DBU) induced 1,2-elimination (-TsH) resulting in the formation of δ-carbolines 1a and benzofuro[3,2-b]pyridines 2a, respectively, with 62–97% yields. On the other hand, exposure of 3 and 4 to iodonium monochloride (ICl) and K₂CO₃ in refluxing DCM triggered a tandem iodocyclization followed by 1,2-elimination (-TsH), delivering 3-iodo δ-carbolines 1b and benzofuro[3,2-b]pyridines 2b, respectively, within 2 h with 44–86% yields. We propose plausible reaction mechanisms for the formation of products 1a–b and 2a–b. A photophysical study on a few selected products revealed their poor emissive property.

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金(I)催化和一氯化碘介导的吲哚/苯并呋喃基乙基底物的碳环：δ-羰基和苯并呋喃[3,2-b]吡啶的易得性。

金(I)催化吲哚/苯并呋喃基n-丙基磺酰胺3和4的串联环化生成二氢δ-羰基和苯并呋喃[3,2-b]吡啶中间体，经碱（DBU）诱导1,2-消去（- tsh），分别生成δ-羰基1a和苯并呋喃[3,2-b]吡啶2a，产率为62-97%。另一方面，3和4在回流DCM中暴露于一氯化碘（ICl）和K2CO3，引发了串联碘环化，然后是1,2-消除（-TsH），在2小时内分别传递了3-碘δ-碳啉1b和苯并呋喃[3,2-b]吡啶2b，产率为44-86%。我们提出了产物1a-b和2a-b形成的合理反应机制。对少数产品的光物理研究表明它们的发射性能很差。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Organic Chemistry 化学-有机化学

CiteScore

6.20

自引率

11.10%

发文量

1467

审稿时长

2 months

期刊介绍： Journal of Organic Chemistry welcomes original contributions of fundamental research in all branches of the theory and practice of organic chemistry. In selecting manuscripts for publication, the editors place emphasis on the quality and novelty of the work, as well as the breadth of interest to the organic chemistry community.