Nickel()/Lewis acid catalysed olefin hydroamination and hydroarylation under mild conditions

• Published in: Organic & biomolecular chemistry 2024-01, Vol.22 (4), p.823-83
• Main Authors: Li, Kaiwen, Jiang, Hongwu, Dong, Shuangfeng, Li, Shuang-Long, Chen, Zhuqi, Yin, Guochuan
• Format: Article
• Language: English
• Subjects: Acrylates; Acrylonitrile; Agrochemicals; Alkenes; Aniline; Catalysis; Catalysts; Lewis acid; Nickel; Protonation; Styrene; Styrenes
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/d3ob01770b

Aniline derivatives are important nitrogen-containing compounds with wide applications in chemicals, pharmaceuticals and agrochemicals. In the work described herein, nickel( ii )/Lewis acid (LA) catalysed olefin hydroamination with anilines was explored for use in aniline derivative syntheses. The Ni( ii )/LA catalysis proceeded smoothly under mild conditions, whereas using Ni(OAc) 2 alone, the catalyst was inactive. Remarkably, the Markovnikov addition type products were obtained when substituted styrenes were used as the olefin source, while the anti-Markovnikov addition type products were obtained when the electron-deficient olefins such as acrylonitrile and acrylates were used. The mechanistic studies revealed that hydroamination of the styrene derivates proceeded via the amino-Ni( ii )/LA attacking the carbocation intermediate which was generated by the protonation of the olefin, whereas for acrylonitrile and acrylates, it proceeded by a direct amino-Ni( ii )/LA attack on the olefin by nucleophilic addition. In addition, the hydroarylation product was generated by the Hofmann-Martius rearrangement of the hydroamination product. The presence of a Lewis acid can promote a Ni(OAc) 2 -catalysed olefin hydroamination reaction proceeding smoothly under mild conditions, whereas Ni(OAc) 2 alone was inactive.