An Efficient Approach to 2-CF3-Indoles Based on ortho-Nitrobenzaldehydes

Vasiliy M Muzalevskiy; Zoia A Sizova; Vladimir T Abaev; Valentine G Nenajdenko

doi:10.3390/molecules26237365

An Efficient Approach to 2-CF₃-Indoles Based on ortho-Nitrobenzaldehydes

Molecules. 2021 Dec 4;26(23):7365. doi: 10.3390/molecules26237365.

Authors

Vasiliy M Muzalevskiy¹, Zoia A Sizova¹, Vladimir T Abaev^{2

3}, Valentine G Nenajdenko¹

Affiliations

¹ Department of Chemistry, Lomonosov Moscow State University, 119899 Moscow, Russia.
² North Ossetian State University, 44-46 Vatutina St., 362025 Vladikavkaz, Russia.
³ North Caucasus Federal University, 1a Pushkin St., 355009 Stavropol, Russia.

Abstract

The catalytic olefination reaction of 2-nitrobenzaldehydes with CF₃CCl₃ afforded stereoselectively trifluoromethylated ortho-nitrostyrenes in up to 88% yield. The reaction of these alkenes with pyrrolidine permits preparation of α-CF₃-β-(2-nitroaryl) enamines. Subsequent one pot reduction of nitro-group by Fe-AcOH-H₂O system initiated intramolecular cyclization to afford 2-CF₃-indoles. Target products can be prepared in up to 85% yields. Broad synthetic scope of the reaction was shown as well as some followed up transformations of 2- CF₃-indole.

Keywords: CF3-group; catalytic olefination reaction; fluorine; indole; nitro group; reduction.

Grants and funding

18-13-00136/Russian Science Foundation