Hydroarylation of unsaturated carbon–carbon bonds in cross-conjugated enynones under the action of superacid CF₃SO₃H or acidic zeolite HUSY. Reaction mechanism and DFT study on cationic intermediate species

Abstract

Reactions of enynones with arenes in TfOH-Py or with zeolite HUSY lead to products of hydroarylation of the acetylene bond.

Cyclization of arylhydrazones of cross-conjugated enynones: synthesis of luminescent styryl-1H-pyrazoles and propenyl-1H-pyrazoles

“…1,5-Diarylpent-1-en-4-yn-3-ones 1a–o and s–v were prepared by the condensation of 4-arylbut-3-yn-2-ones with aromatic and heteroaromatic aldehydes in the presence of NaOH, using a known method; compounds 1a–g , i–o , r , and s have already been characterized previously. 26,39 1-Phenylpent-1-en-4-yn-3-one 1r and 5-phenylpent-1-en-4-yn-3-one 1z were obtained according to the method of Miller and Reiser 20 b and the method of Golovanov and coworkers, 19 b respectively. Arylhydrazones 5a , m–o , and r were synthesized as described previously.…”

Reactivity of Cross-Conjugated Enynones in Cyclocondensations with Hydrazines: Synthesis of Pyrazoles and Pyrazolines

“…Combining the factors of high activity and selectivity allows development of effective methods for synthesis of a variety of heterocycles, such as for pyrrolone, 4-oxodihydrothiopyran, indole, pyrazole, pyrimidine, and other compounds with more complex structures . Just recently, the expansion of pent-1-en-4-yn-3-ones was balanced with operation of current methods of metal complex catalysis , as well as with application of superelectrophilic activation . Finally, the potential of the enynone building blocks is obviously featured by the multistep synthesis of complex natural products .…”

A General Synthesis of Cross-Conjugated Enynones through Pd Catalyzed Sonogashira Coupling with Triazine Esters

“…(E)-1,5-diphenylpent-1-en-4-yn-3-one (3aa) [12], the general method using Triazine Ester 1a and Phenylacetylene 2a gave the title compound 3aa in 95% yield; 1 (E)-5-phenyl-1-(p-tolyl)pent-1-en-4-yn-3-one (3ba) [41], the general method using Triazine Ester 1b and Phenylacetylene 2a gave the title compound 3ba in 94% yield; 1 (E)-1-(4-methoxyphenyl)-5-phenylpent-1-en-4-yn-3-one (3ca) [41], the general method using Triazine Ester 1c and Phenylacetylene 2a gave the title compound 3ca in 90% yield; 1 (E)-1-(4-fluorophenyl)-5-phenylpent-1-en-4-yn-3-one (3da) [41], the general method using Triazine Ester 1d and Phenylacetylene 2a gave the title compound 3da in 85% yield; 1 (E)-5-phenyl-1-(4-(trifluoromethyl)phenyl)pent-1-en-4-yn-3-one (3ea) [42], the general method using Triazine Ester 1e and Phenylacetylene 2a gave the title compound 3ea in 85% yield; 1 (E)-1-(4-chlorophenyl)-5-phenylpent-1-en-4-yn-3-one (3fa) [41], the general method using Triazine Ester 1f and Phenylacetylene 2a gave the title compound 3fa in 80% yield; 1 (E)-5-phenyl-1-(m-tolyl)pent-1-en-4-yn-3-one (3ha), the general method using Triazine Ester 1h and Phenylacetylene 2a gave the title compound 3ha in 93% yield; 1 H NMR (400 MHz, Acetonitrile-d 3 ): δ/ppm = 7.97 (d, J = 16.1 Hz, 1H), 7.80-7.65 (m, 2H), 7.63-7.41 (m, 5H), 7.41-7.19 (m, 2H), 6.89 (d, J = 16.1 Hz, 1H), 2.37(s, 3H). 13 (E)-5-phenyl-1-(o-tolyl)pent-1-en-4-yn-3-one (3ia), the general method using Triazine Ester 1i and Phenylacetylene 2a gave the title compound 3ia in 85% yield; 1 H NMR (400 MHz, Acetonitrile-d 3 ): δ/ppm = 8.03 (d, J = 16.1 Hz, 1H), 7.74-7.64 (m, 3H), 7.50-7.40 (m, 4H), 7.36 (d, J = 5.7 Hz, 1H), 7.28 (t, J = 5.6 Hz, 1H), 6.92 (d, J = 16.1 Hz, 1H), 2.57(s, 3H).…”