Amination of arenes

Amination of arenes. With Znl2 as the catalyst, the reagent is an adequate electrophilic reagent for many arenes. The products are cleaved in one step to provide the amines by treatment with zinc dust in acetic acid. 

The L -iodane PhI(OAc)2 has been used extensively, most notably by Sanford, to oxygenate the C-H bonds of arenes and even alkanes in the presence of palladium catalysts." Interestingly, this reaction was likely mediated by a binuclear complex featuring two Pd(III) atoms joined by a palladium-palladium (Pd-Pd) bond however, this complex can disproportionate into a Pd(IV)-Pd(II) complex without a formal Pd-Pd bond, and this intricate interplay is often controlled by the presence and nature of hypervalent iodine oxidants." We discovered that this reaction manifold could be extended to include the amination of arene substrates heating 2-phenylindole 51 in the presence of the -iodane 49 and palladium acetate provided the ortho-aminated product 52 in a 19% yield however, switching the metal from palladium acetate... 

Homolytic aromatic substitution can also be performed with electrophihc het-eroatom-centered radicals. The radical amination of arenes with electrophilic diaUcyl aminyl radical cations represents a valuable method for the preparation of aniUne derivatives [2e, 111a]. The radical cations (R2HN ) are generally prepared from the corresponding N-chloroamines in an acidic medium, using catalytic amounts of a metal salt [Fe(II)-, Ti(III)-, Cu(I)- and Cr(II)-salts]. The reaction func-... 

Aminations of aromatic nuclei are of obvious synthetic importance and a photoreductive amination of arenes utilizing m-cyano-... 

A Ru(II)-catalyzed ortho C-H amination of arenes with thiophenes and other heteroqrcles at room temperature was achieved this year (130L5286). 

Amines are valuable synthetic targets because of their abundance in medicine, agrochemicals, and materials science [47]. Transition metal-catalyzed direct conversions of aromatic C—H bonds to C—N bonds are attractive synthetic routes toward accessing aryl amines [48]. These reactions are more advantageous over the conventional amination methods that either requires harsh conditions (e.g., nitration followed by reduction) [49] or prefunctionalized substrates (amination of aryl halides) [50, 51]. The Hartwig group recently reported the first example of Pd-catalyzed intermo-lecular amination of arenes (Scheme 24.55) [52a],... 

The reagent system TMS-azide/trillic acid paforms efficient amination of arenes, while the combination of TMS-azide andiV-bromosuccinimide with Nafion-H transforms alkenes into -bromoalkyl azides. On the otha- hand, the combination of TMS-azide and chrominm trioxide converts alkenes into a-azidoketones and aldehydes into acyl azides . 

The orf/io-amination of arenes carrying an A(-alkylbenzamide (DG by alkyl- or benzyl-azides has been reported in a reaction catalysed by cyclopentadienyl rhodium. Isotopic studies indicate that carbon-hydrogen bond cleavage to form a five-membered rhodacy-cle is rate limiting and irreversible. Coordination of the azide gives an intermediate (58) which allows insertion of an A(-alkylamido group. ... 

The amide-directed palladium-catalyzed intermolecular C-H amination of arenes with the non-nitrene-based nitrogen source NFSi was selective at ortho position for para-substituted substrates, while selective at para-position for 2-OMe-substituted substrates (eq 66) 2-alkyl-substituted substrates failed to react. ... 

Chupakhin O, Charushin V, Rusinov V (2003) Nucleophilic momatic substitution of hydrogen - direct method for amination of arenes and hetarenes. In Reikhmemkulov D (ed) Modem organic synthesis. Khimiya, Moscow... 

What about disconnection bl While direct electrophilic amination of arenes is (like aUcoxylation or hydroxylation) not viable, we know that we can achieve it indirectly through a nitration- eduction sequence (Section 16-5). Thus, the problem reduces to a nitration of l-chloro-4-methoxybenzene. Will it proceed with the desired regioselectivity Guideline 2 in Section 16-4 answers in the affirmative. This analysis provides l-chloro-4-methoxybenzene as a new relay point, available, in addition to its ortho isomer, by chlorination of methoxybenzene. 

---