One‐Pot Tandem Synthesis of 2‐Arylbenzoxazole Derivatives via Copper‐Catalyzed CN and CO Bond Formation

Abstract

The reaction of 2-(2-halophenyl)halobenz-

Synthesis of Dibenzodiazepinones via Tandem Copper(I)‐ Catalyzed CN Bond Formation

“…[5] Very recently, Ma and co-workers reported on the synthesis of dibenzodiazepinone from 2-bromo-N- (2-bromophenyl)benz-A C H T U N G T R E N N U N G amide and various primary amines using a Cu(I) catalyst. [6] However, in our recent publication, we found that the product formed is, in fact, the N-substituted-2-(benzo [d]oxazol-2-yl) (B), as confirmed by 1 H NMR, 13 C NMR, LRMS, HR-MS and single crystal X-ray analysis data (Scheme 1) [7] and is not the dibenzodiazepinone derivative (A). Thus, an efficient, one-pot protocol for the synthesis of dibenzodiazepinone derivatives continues to be highly desirable.…”

“…Further, the amides derived from 2-iodobenzoic acid and ortho-substituted anilines reacted smoothly with 2-iodoanilines (2a and 2c) to furnish the corresponding dibenzodiazepinone derivatives in moderate to good yields. It is worth noting that the 2-halo-N-phenylbenzamides derived from electron-withdrawing ortho-substituted anilines such as F, Cl, NO 2 required a longer reaction time than for those with electron-donating groups (entries [3][4][5][6][7][8][9]. Moreover, 2-iodobenzamides derived from m-methoxyaniline and p-isopropylaniline produce compounds 5q and 5r in moderate yields (entries 10 and 11).…”

“…We next investigated the reactions of 2-iodobenz- (6a) as a sole product. [7] Finally, the synthesis of the nitro-substituted dibenzodiazepinone (5n) provided us with the opportunity to carry out a reductive cyclization (Scheme 5). The triaza-pentacyclic compound 7a was obtained in excellent yield, which was confirmed by single crystal X-ray analysis (Figure 2).…”

“…The crude reaction mixture was then purified by column chromatography without work-up using hexane-ethyl acetate as the eluent to yield compound 5a. 15,7 .0 9,14 .0 16,21 ]docosa-1(22), 2,4,6,9(14),10, 12,16(21),17,19-decaene (7a) In a stir-bar-equipped, flame-dried, 50-mL round-bottom flask, 5n (1 mmol) in acetic acid (20 mL) was added, followed by the addition of iron powder (5 mmol). The reaction mixture was then stirred at 80 8C for 6 h. After completion of the reaction as determined by TLC, the reaction mixture was allowed to cool to room temperature.…”

Synthesis of Fused Isoquinolinone and Iminoisoindolinone Derivatives via a Copper‐Catalyzed Regioselective Switching Process

“…In the recent times, copper‐catalyzed tandem sequential cyclization reactions of 2‐halobenzamide derivatives have proven to be powerful tools for the construction of a wide variety of heterocyclic frameworks 7. In our recent research, we focused our attention on copper‐catalyzed CC and CN bond formation reactions of 2‐iodobenzamide derivatives in the construction of various heterocycles, including indoloquinolinone derivatives,8a 2‐aminophenylbenzoxazoles8b and isocoumarin derivatives 8c. On the other hand, it was reported that benzyl cyanide works as a nucleophile in the presence of strong bases 9.…”