Reactivity of 2,1‐Benzisoxazole in Palladium‐Catalyzed Direct Arylation with Aryl Bromides

Abstract

The Pd‐catalyzed direct arylation of 2,1‐benzisoxazole with aryl bromides to access 3‐arylbenzoisoxazoles proceeds in moderate‐to‐high yields with 1 mol % Pd(OAc)2 or 2 mol % PdCl(C3H5)(dppb) (dppb=1,4‐bis(diphenylphosphino)butane) as the catalysts and KOAc as an inexpensive base. A wide variety of (hetero)aryl bromides have been employed successfully. Moreover, arylations followed by benzisoxazole ring opening allowed the preparation of 2‐aminobenzophenones in only two steps.

Synthesis of (2-Aminophenyl)(naphthalen-2-yl)methanones via Intramolecular Rearrangement of (E)-3-Styrylquinolin-4(1H)-ones under Irradiation with 365 nm UV Light

“…In summary, we have developed a highly efficient and environmentally friendly method for the synthesis of (2aminophenyl)(naphthalen-2-yl)methanones by irradiation of (E)-3-styrylquinolin-4(1H)-ones in EtOH-H 2 O (7:1) with 365-nm UV lamps at room temperature under Ar atmosphere. Compared with the previous work, [12][13][14][15][16] the advantages of the described photoinduced rearrangement are: a) transition-metal-catalyst-free, b) additives-free, c) uses ethanol as the solvent, d) tolerates various functional groups, e) involves the construction of naphthalene ring during the rearrangement, and f) exhibits high atom efficiency with high yield.…”

“…A careful review of the literature reports appraised that all the substrates employed in the synthesis of (2-aminophenyl)(naphthalen-2-yl)methanone (E) contain a naphthalene moiety. [12][13][14][15][16] For instance, the palladium-catalyzed cross-coupling of naphthalen-2-ylboronic acid or sodium naphthalene-2-sulfinate (B) with 2-aminobenzonitrile (A) in the presence of ligands at 80 °C for 36-48 hours gave E in 81% or 91% yield (Scheme 1a). 12,13 Alternatively, analogue E could be also obtained from the reduction of 3-(naphthalen-2-yl)benzo[c]isoxazole (C) with hydrogen gas in the presence of Pd/C (Scheme 1b).…”

“…12,13 Alternatively, analogue E could be also obtained from the reduction of 3-(naphthalen-2-yl)benzo[c]isoxazole (C) with hydrogen gas in the presence of Pd/C (Scheme 1b). 14 Interestingly, instead of reduction, the synthesis of analogue E was also reported by the oxidative cleavage of 2-(naphthalen-2-yl)-1H-indole (D) at 120 °C for 16 hours in the presence of Cs 2 CO 3 /O 2 along with the generation of CO 2 (Scheme 1c). 15 The reported method successfully eliminates the requirement of transition metals.…”

Metal‐Free Synthesis of Anthranils by PhIO Mediated Heterocyclization of ortho‐Carbonyl Anilines

“…Arylation at C‐3 position of 2,1‐benzisoxazole with aryl halide [8a] catalyzed by palladium or with diazonium salt under visible light conditions has also been explored [8b] (Scheme 1C). The reaction of nitrobenzene and arylacetonitrile under strongly basic conditions is also reported (Scheme 1D) [9a–c] .…”

Anthranils: versatile building blocks in the construction of C–N bonds and N-heterocycles

“…6 Moreover, palladium-catalysed direct C-H arylation could be applied for the further functionalization of anthranils to synthesize 3-aryl substituted anthranils 5. 7 These practical and efficient methods make anthranils cheap and readily available feedstocks.…”