Cu(II)-Mediated N–H and N-Alkyl Aryl Amination and Olefin Aziridination

Abstract

Cu­(II)-mediated direct NH2 and NH alkyl aryl aminations and olefin aziridinations are described. These room-temperature, one-pot, environmentally friendly procedures replace costly Rh2 catalysts and, in some instances, display important differences with comparable Rh2- and Fe-supported reactions.

Picolinate-Directed Arene meta-C–H Amination via FeCl3 Catalysis

“…In the presence of TEMPO (1 equiv), the yield of 2 was reduced to 41% (Scheme 1e). Additional studies 24 and FeSO 4 26b (Scheme 1f−h, respectively).…”

Fe(II)‐Catalyzed Synthesis of Unactivated Aziridines (N‐H/N‐Me) from Olefins Using O‐Arylsulfonyl Hydroxylamines

“…This method produced a broad array of aziridines, but the toxic byproduct (2,4‐dinitrophenol) led to several challenges such as co‐elution with the product during purification and participation in an undesired aziridine ring‐opening reaction, among others. These limitations could be largely addressed later through the methods developed by Kurti, [7a] Falck, [7c] and our lab [7b] utilizing hydroxylamine‐O‐sulfonic acid (HOSA) and O ‐(mesitylsulfonyl)hydroxylamine (MSH) as the aminating agents (Scheme 1a). Recently, the group of Kurti reported an effective organocatalytic aziridination of unactivated olefins via transient oxaziridines generated from ethyltrifluoropyruvate in the presence of HOSA:Cs 2 CO 3 in hexafluoroisopropanol (HFIP) [8] .…”

Cu(OTf)2-Catalyzed Beckmann Rearrangement of Ketones Using Hydroxylamine-O-sulfonic Acid (HOSA)

“…Generally, acetophenones with strong aryl electron-donating groups reacted smoothly at room temperature to deliver the derived Nphenylacetamides in very good yields, for example, phenol 2b, 4-methoxy 2c, 3,4-dimethoxy 2d, and 4-allyloxy 2e. The latter is notable for its chemoselectivity, that is, no allylic 20 or CH amination 21 or aziridination 17c under the reaction conditions. In contrast, 4-tolyl 2f, phenyl 2g, and naphthyl 2h required heating for a reasonable reaction rate, although room temperature reactivity was restored in the homologous 2i, j.…”