A novel and versatile method for the synthesis of 2H-imidazoles via iron-catalyzed [3 + 2] annulation from readily available oxime acetates with vinyl azides has been developed. This denitrogenative process involved N–O/N–N bond cleavages and two C–N bond formations to furnish 2,4-substituted 2H-imidazoles. This protocol was performed under mild reaction conditions and needed no additives or ligands
Deoximation of Oxime<i>O</i>-Acetates, Oximes, and Oxime Ethers by Nonacarbonyldiiron or Pentacarbonyliron. An Electronic Effect for the N–O Bond Cleavage
The reaction of [Fe2(CO)9] or [Fe(CO)5] with oxime O-acetates, oximes, and oxime ethers under photoirradiation or thermal conditions undergoes deoximation to give the corresponding ketones. The oxime O-acetate was found to be the most reactive class of these compounds. A proposed mechanism involves an initial complexation of the [Fe(CO)4] species to the nitrogen atom of the oxime group, and the subsequent
acetates and xanthates for the synthesis of thiazol-2-yl ethers with remarkable regioselectivity has been developed. Various oxime acetates, whether derived from aryl ketones or alkyl ketones, or natural product cores are suitable for this conversion. Unique dihydrothiazoles were also obtained when both reaction sites were methine. Mechanistic studies indicated that imino copper(III) intermediates were involved
Metal Carbonyl-Induced N–O Bond Cleavage of the Oxime Group
作者:Makoto Nitta、Yukio Iino
DOI:10.1246/bcsj.59.2365
日期:1986.7
The reaction of [Mo(CO)6] or [Fe2(CO)9] with oxime O-acetate of 1,3-diphenyl-2-propen-1-one undergoes a reductive N–O bond cleavage to give an imine which dimerises and/or is hydrolyzed to ketones. The dimer, so formed, undergoes fragmentations to give pyridine and pyrimidine derivatives. Similarly, the reaction of [Mo(CO)6] with several oxime O-acetates, oximes, and an oxime ether were shown to give the corresponding ketones. A reaction of oxime O-acetates with [Cr(CO)6] or with [W(CO)6] to give the corresponding ketones was also shown to proceed very slowly.
Divergent Iron-Catalyzed Coupling of<i>O</i>-Acyloximes with Silyl Enol Ethers
作者:Hai-Bin Yang、Nicklas Selander
DOI:10.1002/chem.201605636
日期:2017.2.3
An iron‐catalyzedcoupling reaction of O‐acyloximes and O‐benzoyl amidoximes with silyl enol ethers is reported. The protocol provides access to functionalized pyrroles, 1,6‐ketonitriles, pyrrolines and imidazolines via carbon‐centered radicals generated from an initially formed iminyl radical. The intramolecular cyclization and ring‐opening processes of the iminyl radical take place preferentially