Ni(II)-catalyzed intramolecular C-H/C-H oxidative coupling: an efficient route to functionalized cycloindolones and indenoindolones
| Title | Ni(II)-catalyzed intramolecular C-H/C-H oxidative coupling: an efficient route to functionalized cycloindolones and indenoindolones |
| Publication Type | Journal Article |
| Year of Publication | 2021 |
| Authors | Ankade, SB, Samal, PParamita, Soni, V, Gonnade, RG, Krishnamurty, S, Punji, B |
| Journal | ACS Catalysis |
| Volume | 11 |
| Issue | 19 |
| Pagination | 12384-12393 |
| Date Published | OCT |
| Type of Article | Article |
| ISSN | 2155-5435 |
| Keywords | C-H activation, cycloindolones, indenoindolones, indoles, Mechanism, Nickel, oxidative coupling |
| Abstract | Nickel(II)-catalyzed intramolecular C(sp(2))-H/C(sp(3))-H and C(sp(2))-H/C(sp(2))-H oxidative couplings in indoles are achieved via chelation assistance. These reactions provide access to biologically relevant five- and six-membered substituted cyclopentaindolones, carbazolones, and indenoindolones in high yields and good chemoselectivity employing an air-stable and defined nickel catalyst, (bpy)Ni(OAc)(2). The oxidative cyclizations proceeded either through a six-membered or an unconventional seven-membered nickelacycle. An extensive mechanistic investigation by experiments and theoretical calculations revealed a facile indole's C(2)-H nickelation and a rate-limiting reductive elimination process. This intramolecular oxidative cyclization operates via a probable Ni(II)/Ni(III) pathway involving single-electron oxidation of nickel without the participation of a carbon-based radical. |
| DOI | 10.1021/acscatal.1c03314 |
| Type of Journal (Indian or Foreign) | Foreign |
| Impact Factor (IF) | 13.084 |
Divison category:
Catalysis and Inorganic Chemistry
Center for Material Characterization (CMC)