Microwave-Assisted Selective Nucleopalladation-Triggered Cascade Process: Synthesis of Highly Functionalized 3-Chloro-1H-indenes.

IF 3.3 2区化学 Q1 CHEMISTRY, ORGANIC

The Journal of Organic Chemistry Pub Date : 2024-09-20 Epub Date: 2024-09-04 DOI:10.1021/acs.joc.4c01011

Tanvi Jandial, Anish Gupta, Dolma Tsering, Kamal K Kapoor, Vellaisamy Sridharan

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Abstract

A nucleopalladation-triggered cascade transformation of internal alkynes bearing an amino nucleophile and an electrophilic enone was investigated under unconventional microwave-assisted conditions. Among the three possible pathways, the chloropalladation-triggered domino process proceeded selectively to furnish 3-chloro-1H-indenes in good to excellent yields. The reactions under microwave irradiation were completed in 30 min, and the conventional heating required 3-5 h for completion. The yields obtained under nonclassical heating using microwave irradiation are marginally higher (71-97%) than those of the conventional heating conditions (67-96%). The mechanism of this domino process involves chloropalladation of alkynes to deliver σ-vinylpalladium intermediates, intramolecular carbopalladation via Heck-type olefin insertion, and protodepalladation steps. The other two competitive intramolecular aminopalladation-initiated cascades via 7-endo-dig or 6-exo-dig cyclizations leading to oxazepine or benzoxazine scaffolds were not observed.

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微波辅助的选择性核钯化触发级联过程：高功能化 3-氯-1H-茚的合成。

研究人员在非常规微波辅助条件下，对带有一个亲氨基核团和一个亲电烯酮的内炔进行了钯化引发的级联转化。在三种可能的途径中，氯钯化触发的多米诺过程选择性地生成了 3-氯-1H-茚，收率从良好到极佳。微波辐照下的反应在 30 分钟内完成，而常规加热则需要 3-5 小时才能完成。使用微波辐照进行非传统加热的产率（71-97%）略高于传统加热条件下的产率（67-96%）。这一多米诺过程的机理包括炔烃的氯钯化以提供σ-乙烯基钯中间体、通过赫克型烯烃插入进行分子内碳钯化以及原去钯化步骤。另外两种竞争性分子内氨钯化引发的级联反应是通过 7-endo-dig 或 6-exo-dig 环化反应生成草氮平或苯并噁嗪支架，但没有观察到这两种反应。

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来源期刊

The 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： The 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.