Efficient Buchwald–Hartwig and nitrene-mediated five-membered ring closure approaches to the total synthesis of quindoline. Unexpected direct conversion of a nitro group into a phosphazene

2024-07-052024-07-052023-05-052046-2069https://hdl.handle.net/2133/27436Two total syntheses of quindoline, which take place through the intermediacy of 3-nitroquinoline derivatives, are reported. The general synthetic sequence involves construction of the latter by mechanochemical condensation of benzaldehydes with 2-amino-nitrostyrene, followed either by reduction of the nitro group of the heterocycle and Buchwald–Hartwig cyclization or by a nitrenemediated cyclization under solventless conditions. Use of PPh3 to generate the nitrene resulted in the unprecedented formation of a phosphazene in place of quindoline. This unexpected transformation was explained by means of DFT computations.13715–13724enopenAccessBenzaldehydesCyclizationQuindolineBuchwald–hartwig aminationEfficient Buchwald–Hartwig and nitrene-mediated five-membered ring closure approaches to the total synthesis of quindoline. Unexpected direct conversion of a nitro group into a phosphazenearticuloThobokholt, Elida N.Simonetti, Sebastián OsvaldoKaufman, Teodoro SaúlLarghi, Enrique LeandroBracca, Andrea Beatriz JuanaUniversidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y FarmacéuticasAttribution-NonCommercial 4.0 International