Efficient Conversion of Acetophenones into 1,3,5-Triarylbenzenes Catalyzed by Bismuth(III) Trifluoromethanesulfonate Tetrahydrate

Abstract

Bismuth(III) trifluoromethanesulfonate tetrahydrate is found to efficiently catalyze the cyclotrimerization of acetophenones into 1,3,5-triarylbenzenes in good yields.

DBSA catalyzed cyclotrimerization of acetophenones: An efficient synthesis of 1,3,5-triarylbenzenes under solvent-free conditions

“…The compounds, 2a-g and 2i-l are known and their spectral and analytical data are found to be in agreement with the reported data [11,14,16,18] while the characterization data of unknown compounds (2h, 2m and 2n) are given below. 1599, 1459, 1401, 1359, 1330, 1281, 1234, 1165, 1125, 1099, 1074, 1042, 911, 872, 801, 704, 674, 661, 71, 129.49, 125.88, 124.60 (d, 4 J CÀF = 3.83 Hz), 124.14 (d, 4 J CÀF = 2.88 Hz), 124.09 (d, 1 62.44;H,3.10.…”

“…Consequently, a number of synthetic methods have been developed previously to construct 1,3,5-triarylbenzenes. The most common strategies for their synthesis include the metal catalyzed cyclotrimerization of alkynes [9], cross coupling reactions of aryl halides with organometallic species [10] and triple self-condensation of aryl methyl ketones in the presence of an acidic catalyst such as PTSA [11], TiCl 3 (OTf) [12], TiCl 4 [13], Bi(OTf) 3 .4H 2 O [14], phosphomolybdic acid [15], Nafion-H [16], potassium pyrosulfate and sulfuric acid [17], Amberlyst-15 [18], H 3 PW 12 O 40 @nano-SiO 2 [19], zirconocene bis(perfluoroctanesulfonate)s [20], ethylenediamine and trifluoroacetic acid [21]. Although these processes have proved useful for the preparation of these compounds, there are some limitations including low yields, long reaction times, harsh reaction conditions, use of hazardous organic solvents, expensive metal catalysts, tedious workup procedures or requirement of special apparatus.…”

Insights into the triple self-condensation reaction of thiophene-based methyl ketones and related compounds

“…15 The triple self-condensation of starting acetophenones (AP) and hetaryl methyl ketones (HetAP) takes place mostly in ethanol using Brønsted or Lewis acids such as common SiCl 4 , [16][17][18][19][20] TiCl 4 , 21,22 p-TsOH 23 and variations on more complex structures. [23][24][25][26][27][28] Although these processes provide regioselective approaches to polysubstituted aromatic compounds, as has been presented in a large number of studies, [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] there are some limitations including low yields, long reaction times, harsh reaction conditions, use of expensive metal catalysts, tedious work-up, and formation of side products.…”