1.
J Am Chem Soc
; 146(7): 4795-4802, 2024 Feb 21.
Artículo
en Inglés
| MEDLINE
| ID: mdl-38329998
RESUMEN
An iron/chromium system (Fe(OAc)2, CpCr(CO)3H) catalyzes the preparation of ß,γ- or γ,δ-unsaturated amides from 1,4,2-dioxazol-5-ones. An acyl nitrenoid iron complex seems likely to be responsible for C-H activation. A cascade of three H⢠transfer steps appears to be involved: (i) the abstraction of H⢠from a remote C-H bond by the nitrenoid N, (ii) the transfer of H⢠from Cr to N, and (iii) the abstraction of H⢠from a radical substituent by the Crâ¢. The observed kinetic isotope effects are consistent with the proposed mechanism if nitrenoid formation is the rate-determining step. The Fe/Cr catalysts can also desaturate substituted 1,4,2-dioxazol-5-ones to 3,5-dienamides.