Construction of N-Acyliminophosphoranes via Iron(II)-Catalyzed Imidization of Phosphines with N-Acyloxyamides

Abstract

Employing FeCl 2 as a cheap and readily available catalyst, a facile imidization of phosphines with N-acyloxyamides is described, affording synthetically useful N-acyliminophosphoranes with high functional group tolerance. The transformation is easily performed under an air atmosphere at room temperature and could be scaled up to gram scale with a catalyst loading of 1 mol %. The iminophosphoranyl moiety in the product was further utilized as an effective directing group for controllable ortho C(sp 2 )−H bond amidations under Rh(III) catalysis.

Nitrene transfer reaction with hydroxylamine derivatives

“…59 In addition, their group achieved a facile imidization of phosphines with N-acyloxyamides by using FeCl 2 as the catalyst (Scheme 31c). 60 Lebel et al documented a diastereoselective amination of thioethers with chiral N-mesyloxycarbamate S-14 for the synthesis of chiral sulfilimines (Scheme 32). 61,62 The reaction was performed with Rh 2 [(S)-nttl] 4 previously used for asymmetric Csp 3 -H amination, and its structure has been shown in Scheme 8.…”

“…59 In addition, their group achieved a facile imidization of phosphines with N -acyloxyamides by using FeCl 2 as the catalyst (Scheme 31c). 60…”

Photoredox Catalytic Phosphine-Mediated Deoxygenation of Hydroxylamines Enables the Construction of N-Acyliminophosphoranes

“…Bittner and Pomerantz demonstrated that amide could be converted to phosphinimidic amides by treatment with stoichiometric quantities of phosphines and diethyl azodicarboxylate (DEAD) . More recently, the transformation of nitrene has been regarded as a powerful access to this class of compounds. − Under photoirradiation, dibenzothiophene N -substituted sulfilimines and dioxazolones were utilized as nitrene precursors by the groups of Morita and Bao, respectively. During the preparation of this manuscript, Xia and co-workers reported an Fe­(II)-catalyzed imidization of phosphines with N- pivaloyloxyamides …”

“…During the preparation of this manuscript, Xia and co-workers reported an Fe(II)-catalyzed imidization of phosphines with N-pivaloyloxyamides. 12 Taking advantage of the rapidly developed photochemistry, 13 phosphoranyl radical-mediated fragmentation provided an attractive way to access carbon-centered radicals via the deoxygenation of carboxylic acids and alcohols (Scheme 1B). 14,15 However, the activation of N−O bond for the generation of nitrogen-centered radicals 16 is less developed.…”

Iron(II)-Catalyzed Nitrene Transfer Reaction of Sulfoxides with N-Acyloxyamides

“…On the basis of our previous mechanistic investigations on the C–H activation reactions, we found N -acyloxyamides could serve as mild and stable N -acyl nitrene precursors . Following our interests in the field, in the current report we applied the N -acyloxyamides for N -acyl nitrene transfer of sulfoxides using iron­(II) salt as the catalyst, opening a facile access to various N -acyl sulfoximines [Scheme b, (3)].…”