Facile Amine Formation by Intermolecular Catalytic Amidation of Carbon−Hydrogen Bonds

Abstract

A simple copper-based catalytic system has been developed for the carbon-hydrogen amidation reaction. The copper-homoscorpionate complex Tp(Br3)Cu(NCMe) catalyzes the transfer of the nitrene unit NTs (Ts = p-toluenesulfonyl) and its subsequent insertion into the sp(3) C-H bonds of alkyl aromatic and cyclic ethers or the sp(2) C-H bonds of benzene using PhI=NTs as the nitrene source, affording the corresponding trisubstitued NR(1)HTs amines in moderate to high yields. The use of the environmentally friendly chloramine-T has also proven effective, with the advantage that sodium chloride is formed as the only byproduct. A tandem, one-pot consecutive nitrene-carbene insertion system has been developed to yield amino acid derivatives.

Highly Regioselective Copper‐Catalyzed Benzylic CH Amination by N‐Fluorobenzenesulfonimide

“…The results shown in Scheme 4 (6 a/6 a' and 6 b/6 b') indicate the remarkable preference for primary over second C À H bonds in the amination reaction; this preference is in sharp contrast to the previous reports. [11,12] Although the mechanistic details of this transformation are not clear at the moment, we presently favor the catalytic cycle involving Cu I , Cu II , and Cu III species (Scheme 5). In the presence of ligands, the oxidation of CuCl with NFSI provides the Cu III complex A, which abstracts a benzylic hydrogen atom [14,31] from substrate 1 to give the benzylic radical intermediate B and the Cu II species C. The subsequent oxidation of the benzylic radical by the Cu II species C leads to the formation of the amination product 2 along with CuCl for the next catalytic cycle.…”

“…However, because of the favored electronic effect of the secondary C À H bond (for example, the major product of path a in Scheme 1), the selective amination of primary C À H bonds, for example in 1-ethyl-4-methylbenzene, remains a great challenge. [11,12] In addition, to our knowledge, no efficient method exists for direct diamination of the two methyl groups in xylene. Even for the amination reactions of toluene, a large excess of toluene (15-500 equiv) is usually necessary.…”

Metal‐Free [2+2+1] Annulation of Alkynes, Nitriles and Nitrogen Atoms from Iminoiodanes for Synthesis of Highly Substituted Imidazoles

“…Therefore, we envisaged that the iodine(III)-mediated oxidative annulation could be extended to a metal-free approach to the synthesis of highly substituted imidazoles by the use of N-sulfonyliminophenyliodane (PhINSO 2 R) and an acid additive instead of PhI(OH)X (Scheme 1b). Under transition metalcatalyzed conditions, PhINSO 2 R [12] has been well known to serve as an excellent nitrenoid precursor in the aziridination of alkenes, [13] the C À H amidation of alkanes, arenes and aldehydes, [14] and so on. [15] Very recently, it has been reported that ArINSO 2 R medi-ates the aziridination of alkenes [16] and C À H amidation of aldehydes and 1,3-dicarbonyl compounds [17] without any metal catalyst.…”

Evidence for a One‐Electron Mechanistic Regime in Dirhodium‐Catalyzed Intermolecular CH Amination

“…[1,2] Although several transition metals have been shown to accomplish oxidative CÀH amination, [3][4][5][6][7][8][9][10][11][12] metal-metal bonded dirhodium complexes are the best catalysts for this process in terms of their efficiency and selectivity, and are therefore utilized in a number of synthetic applications. [13,14] Despite the successful application of dirhodium-catalyzed CÀH aminations, a major drawback is that very little is known about the mechanism of the reaction.…”