Asymmetric fluorination of 4-substituted pyrazolones catalyzed by quinine. Issue 9 (1st June 2016)

• Record Type: Journal Article
• Authors: Bao, Xiaoze; Wei, Shiqiang; Zou, Liwei; Song, Yuming; Qu, Jingping; Wang, Baomin
• Is Part Of: Tetrahedron, asymmetry. Volume 27:Issue 9/10(2016)
• Page Start: 436
• Page End: 441
• Publication Date: 2016-06-01
• Subjects: Asymmetry (Chemistry) -- Periodicals; 547.005
• DOI: 10.1016/j.tetasy.2016.03.013
• Languages: English
• ISSNs: 0957-4166

Abstract

Graphical abstract: Abstract: An asymmetric fluorination process of 4-substituted pyrazolones catalyzed by quinine is revealed. The reaction afforded a wide range of 4-fluorinated pyrazol-5-ones with excellent yields (up to 98%) and moderate to good enantioselectivities (up to 81% ee ). Abstract : 4-Benzyl-4-fluoro-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C22 H17 FN2 O 51% ee [ α ]D 22 = −51.6 ( c 0.28, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-4-(4-fluorobenzyl)-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C22 H16 F2 N2 O 40% ee [ α ]D 22 = −45.0 ( c 0.55, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-1, 3-diphenyl-4-(4-(trifluoromethyl)benzyl)-1 H -pyrazol-5(4 H )-one: C23 H16 F4 N2 O 41% ee [ α ]D 22 = −51.1 ( c 0.36, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-4-(2-nitrobenzyl)-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C22 H16 FN3 O3 42% ee [ α ]D 22 = −37.4 ( c 0.56, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-4-(3-methylbenzyl)-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C23 H19 FN2 O 71% ee [ α ]D 26 = −95.2 ( c 0.46, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-4-(4-methoxybenzyl)-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C23 H19 FN2 O2 67% ee [ α ]D 25 = −65.8 ( c 0.55, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-4-(2-methylbenzyl)-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C23 H19 FN2 O 68% ee [ α ]D 25 = −75.4 ( c 0.50, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-4-(furan-2-ylmethyl)-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C20 H15 FN2 O2 57% ee [ α ]D 22 = −69.0 ( c 0.45, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-1, 3-diphenyl-4-(thiophen-2-ylmethyl)-1 H -pyrazol-5(4 H )-one: C20 H15 FN2 OS 45% ee [ α ]D 22 = −76.0 ( c 0.58, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-4-(naphthalen-1-ylmethyl)-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C26 H19 FN2 O 81% ee [ α ]D 26 = −89.8 ( c 0.55, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Allyl-4-fluoro-1, 3-diphenyl-1 H -pyrazol-5(4 H )-one: C18 H15 FN2 O 35% ee [ α ]D 26 = −43.5 ( c 0.47, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Fluoro-1, 3-diphenyl-4-(prop-2-ynyl)-1 H -pyrazol-5(4 H )-one: C18 H13 FN2 O 40% ee [ α ]D 21 = −35.7 ( c 0.45, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Benzyl-3-(4-bromophenyl)-4-methyl-1-phenyl-1 H -pyrazol-5(4 H )-one: C23 H19 BrN2 O 37% ee [ α ]D 26 = −19.4 ( c 0.66, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Benzyl-4-fluoro-1-phenyl-3-p-tolyl-1 H -pyrazol-5(4 H )-one: C23 H19 FN2 O 51% ee [ α ]D 26 = −43.5 ( c 0.53, CH2 Cl2 ) Source of chirality: asymmetric fluorination Abstract : 4-Benzyl-4-fluoro-3-(4-methoxyphenyl)-1-phenyl-1 H -pyrazol-5(4 H )-one: C23 H19 FN2 O2 53% ee [ α ]D 26 = −28.1 ( c 0.46, CH2 Cl2 ) Source of chirality: asymmetric fluorination