Selective N-Arylation of Aminobenzanilides under Mild Conditions Using Triarylbismuthanes

Abstract

Diarylamines are prepared selectively in good yields under mild conditions by treatment of aminobenzanilides with triarylbismuthanes in the presence of copper(II) acetate and triethylamine. Arylation under these conditions occurs preferentially at the amino- rather than the amide-nitrogen of the benzanilide. Thus, heating an aminobenzanilide in dichloromethane under reflux in the presence of 1 equiv each of a triarylbismuthane, triethylamine, and copper(II) acetate affords the diarylamine in good yields. This method thereby provides a mild and expeditious route to functionalized diarylamines.

Ligand-free copper(I) catalyzed N- and O-arylation of aryl halides

“…Another major drawback of this protocol is the use of stoichiometric amounts of copper or copper salts, which results in the production of large quantities of waste, making this method environmentally unfriendly. Milder reactions using transmetallating agents, such as triarylbismuth, 3 aryllead triacetates, 4 arylboronic acids 5 and hypervalent aryl siloxanes, 6 have been developed but these alternatives are limited since the preparation of highly functionalized substrates usually requires multistep sequences. Important developments have been made on the Ullmann-type coupling reaction, mainly improving the reaction conditions and tolerability of substrates.…”

Tris(polymethoxyphenyl)bismuth derivatives: Synthesis and reactivity

“…The reactions of 2-naphthol 20 and of the b-ketoester 25 with organobismuth derivatives 11, 13,14 and 16 were realized in THF (tetrahydrofurane) equivalent of TMG (N,N,N 0 ,N 0 -tetramethylguanidine) used as the base. The expected arylation products 21-24 and 26-29, respectively, were obtained in good to high yields (Table 2).…”

“…1 H NMR: d = 3.71 (s, 9H, OMe), 3.77 (s, 9H, OMe), 6.40 (dd, 3H, J = 7.9 and J = 2.2 Hz, 5-H), 6.53 (d, 3H, J = 2.2 Hz, 3-H) and 7.28 (d, 3H, J = 7.9 Hz, 6-H) ppm. 13 Method A: A mixture of sodium perborate, monohydrate (4.2 mmol) and triarylbismuthane (1.4 mmol) in acetic acid (15 mL) was stirred at room temperature for 30 min. The resulting mixture was poured into water (40 mL) and was extracted with CH 2 Cl 2 (3 · 20 mL).…”

“…1 H NMR: d = 1.24 (t, 3H, J = 7.1 Hz, CH 3 CH 2 O), 4H,4H,3.82 and 3.84 (s,6H,OMe),4.18 (q,2H,J = 7.1 Hz, OCH 2 CH 3 ) and 3H,ArH) ppm. 13 Ethyl 1-(2 0 ,4 0 -dimethoxyphenyl)-2-oxocyclohexanecarboxylate (27): CC (pentane/ether,7:3); colourless oil; 43%. 1 H NMR: d = 1.19 (t,3H,J = 7.1 Hz, OCH 2 CH 3 ), 4H,4H,3.72 and 3.94 (s,6H,OMe),2H,OCH 2 CH 3 ), 6.41-6.50 (m, 2H, 5 0 -H and 3 0 -H) and 6.98 (d, 1H, J = 9.2 Hz, 6 0 -H) ppm.…”

“…On the other hand, Suzuki et al reported the strong influence of an ortho-methoxy group on the basicity and reactivity of triarylbismuth derivatives [11]. However, the presence of an ortho-alkoxy group is not detrimental to the reactivity of these compounds in ligand coupling reactions [12,13]. In view of the interest of C-, Nand O-arylation reactions with electron-rich aryl groups for the synthesis of natural and/or biologically active compounds [14], we have investigated the synthesis of tris(polymethoxyphenyl)bismuth derivatives and we have studied their reactivity in typical examples of C-, N-and O-arylation reactions.…”