A straightforward conversion of 1,4-quinones into polycyclic pyrazoles via [3 + 2]-cycloaddition with fluorinated nitrile imines

• Greta Utecht-Jarzyńska,
• Karolina Nagła,
• Grzegorz Mlostoń,
• Heinz Heimgartner,
• Marcin Palusiak and
• Marcin Jasiński

Beilstein J. Org. Chem. 2021, 17, 1509–1517, doi:10.3762/bjoc.17.108

• -thiadiazoles as the products of [3 + 2]-cycloaddition to the C=S bond [25]. Taking into account that fluorinated heterocycles [31][32][33][34], including pyrazoles [31][35][36], are of great significance for various medicinal and agricultural applications, the development of new methods for the construction of

Synthesis of 4-amino-5-fluoropyrimidines and 5-amino-4-fluoropyrazoles from a β-fluoroenolate salt

• Tobias Lucas,
• Jule-Philipp Dietz and
• Till Opatz

Beilstein J. Org. Chem. 2020, 16, 445–450, doi:10.3762/bjoc.16.41

• the formation of fluorinated heterocycles. While attempts to obtain an aminooxazole upon reaction with hydroxylamine were unsuccessful, substituted hydrazines turned out to provide moderate yields of fluorinated pyrazoles. Phenylhydrazine (12a) was chosen as the model substrate for optimization (Table

• potassium 2-cyano-2-fluoroethenolate was developed. A broad substrate scope was tested and mostly excellent yields were obtained. The synthesis of fluorinated aminopyrazoles from the same fluorinated precursor could be demonstrated but proceeded with lower efficiency. Keywords: cyclization; fluorinated

• heterocycles; fluorine; pyrazoles; pyrimidines; Introduction Due to its extremely widespread application in virtually all areas of synthetic organic chemistry, fluorine is considered a “magic” element. It confers metabolic stability and other unique properties to organic molecules and a large fraction of

Ring-size-selective construction of fluorine-containing carbocycles via intramolecular iodoarylation of 1,1-difluoro-1-alkenes

• Takeshi Fujita,
• Ryo Kinoshita,
• Tsuyoshi Takanohashi,
• Naoto Suzuki and
• Junji Ichikawa

Beilstein J. Org. Chem. 2017, 13, 2682–2689, doi:10.3762/bjoc.13.266

• ; Introduction As 1,1-difluoro-1-alkenes have an electron-deficient carbon–carbon double bond, they readily undergo intramolecular substitution of nucleophiles through an addition–elimination mechanism [1][2]. Thus, under basic conditions, they serve as useful precursors for ring-fluorinated heterocycles and

Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains

• Layal Hariss,
• Kamal Bou Hadir,
• Mirvat El-Masri,
• Thierry Roisnel,
• René Grée and
• Ali Hachem

Beilstein J. Org. Chem. 2017, 13, 2115–2121, doi:10.3762/bjoc.13.208

• fluorinated propargylic derivatives [21]. Thus, taking into account the known biological properties of the imidazo-fused N-heterocycles, we became interested in the preparation of new derivatives of this type possessing gem-difluorinated side chains as indicated in Figure 1. Such new fluorinated heterocycles

Synthesis of 2-trifluoromethylpyrazolo[5,1-a]isoquinolines via silver triflate-catalyzed or electrophile-mediated one-pot tandem reaction

• Xiaoli Zhou,
• Meiling Liu,
• Puying Luo,
• Yingjun Lai,
• Tangtao Yang and
• Qiuping Ding

Beilstein J. Org. Chem. 2014, 10, 2286–2292, doi:10.3762/bjoc.10.238

• interest in developing an efficient method for the synthesis of fluorinated heterocycles. Perfluoroalkynoate is a versatile and powerful building block for generating functionalized perfluoroalkylated compounds, especially fluorinated heterocycles, by tandem reactions [19][20][21][22][23][24][25][26]. For

• example, 2-perfluoroalkynoates have been widely used in synthesizing fluorinated heterocycles, such as benzodiazepines [22], chromenes [21][25], and 2-oxopyridine-fused 1,3-diazaheterocycles [26]. As part of our ongoing efforts in developing synthetic approaches for the functionalization of isoquinoline

• cores [11][14] and the synthesis of novel fluorinated heterocycles [27] with potential biological applications, herein, we describe an efficient method for the one-pot synthesis of trifluoromethylated pyrazolo[5,1-a]isoquinoline derivates via a Lewis acid (AgOTf) or an electrophile- (I2 or ICl) promoted

Aminofluorination of 2-alkynylanilines: a Au-catalyzed entry to fluorinated indoles

• Antonio Arcadi,
• Emanuela Pietropaolo,
• Antonello Alvino and
• Véronique Michelet

Beilstein J. Org. Chem. 2014, 10, 449–458, doi:10.3762/bjoc.10.42

• ready available o-alkynylaniline derivatives should provide a viable alternative to the desired C-3 fluorinated indoles. Catalytic aminofluorination of alkenes and alkynes is receiving growing attention as efficient way to construct fluorinated heterocycles [22][23]. In particular, Au-catalyzed

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

9,10-Dioxa-1,2-diaza-anthracene derivatives from tetrafluoropyridazine

• Graham Pattison,
• Graham Sandford,
• Dmitrii S. Yufit,
• Judith A. K. Howard,
• John A. Christopher and
• David D. Miller

Beilstein J. Org. Chem. 2010, 6, No. 45, doi:10.3762/bjoc.6.45

• fluorinated heterocycles for the preparation of novel heterocyclic structures and focussed upon the synthesis of ring fused systems that could be derived from the reaction of tetrafluoropyridazine (3) with catechol (4). In principle, two possible systems 5 and 6 may be formed depending upon the

• activating effect of ring nitrogen directly opposite the site of nucleophilic substitution. Conclusions A small range of dioxa-1,2-diaza-anthracene analogues 5 and 9 have been synthesised from tetrafluoropyridazine in two efficient steps, further expanding the application of highly fluorinated heterocycles