- 1,2-Dicarbofunctionalization of Trifluoromethyl Alkenes with Pyridinium Salts via a Cycloaddition/Visible-Light-Enabled Fragmentation Cascade
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Although trifluoromethyl alkenes have great synthetic potential, their 1,2-difunctionalization has been a challenge. In this Letter, we disclose the first 1,2-dicarbofunctionalization of trifluoromethyl alkenes with pyridinium salts via a cascade process
- Chen, Guo-Shu,Chen, Shu-Jie,Deng, Tao,He, Zhi-Qing,Li, Jia-Hui,Liu, Li-Shan,Liu, Yun-Lin,Ren, Hai
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supporting information
p. 702 - 707
(2022/01/28)
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- Facile one-pot tandem synthesis of perfluoroalkylated indolizines under metal-free mild conditions
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A direct metal-free method for the synthesis of perfluoroalkylated indolizines by means of DIPEA-promoted tandem C[sbnd]N/C[sbnd]C bond formation was developed. Various substituted pyridines and bromoacetyl derivatives with methyl perfluoroalk-2-ynoates proceeded smoothly in this mild transformation, and the desired products were obtained in good to excellent yields under air.
- He, Dong,Xu, Yuhong,Han, Jing,Deng, Hongmei,Shao, Min,Chen, Jie,Zhang, Hui,Cao, Weiguo
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p. 938 - 944
(2017/01/25)
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- Synthesis and Nitration of Some Thieno-fused Analogues of the Benzo[a]quinolizinium Cation
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Three thieno-fused analogues of benzo[a]quinolizinium (1), thieno[3,2-a]- and thieno[2,3-a]quinolizinimn 4 and 5 and thiazolo[2,3-a]isoquinolinium (6), were synthesized by photocyclization of 1-(2-thienylvinyl)pyridinium salts 9a and 9b and 3-styrylthiazolium salt 9c, respectively. The nitration of the compounds 4, 5, and 6 occurred predominantly at positions 2, 3, and 7, respectively, while the nitro group was introduced into the 8- and 10-positions of 1 in the ratio of 68:32. The nmr and uv spectral properties and reduction potentials of 4-6 were also compared with those of the parent compound 1.
- Sato, Kiyoshi,Arai, Sadao,Yamagishi, Takamichi
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- Pyridinium Ylides in Syntheses of Naphthopyrandiones and in Regioselective Syntheses of Acylated Anthraquinones Related to Fungal and Bacterial Metabolites
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Improvements have been made in the use of acylated pyridinium ylides for the transformation of 2-methyl-1,4-naphthoquinone into derivatives (15) and (16) of naphthopyran-5,10-dione, containing furan and thiophene groups.The substitution and cyclisation steps can be combined effectively by using 2-phenoxymethyl- instead of 2-methyl-naphthoquinone.The use of better leaving groups than phenoxy (especially 4-nitrophenoxy) allows the quinone to react with two proportions of ylide and leads regiospecifically to 1-aroyl-2-arylanthracene-9,10-diones such as (20a).If the leaving group is nuclear bromine as in 2-bromo-3-methyl-1,4-naphthoquinone, another reaction with 2 mol equiv. of ylide leads to complex red intermediates of type (31) which in contact with alumina are quantitatively converted into the regioisomeric 2-aroyl-3-arylanthracene-9,10-diones such as (22a).The structures have been determined by standard methods but special features of the NMR spectra are reported including a case of extreme line broadening by traces of iron.Mechanisms are suggested for the diverse reactions between the quinones and the ylides.
- Aldersley, Michael F.,Chishti, Shuhid H.,Dean, Francis M.,Douglas, Mark E.,Ennis, David S.
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p. 2163 - 2174
(2007/10/02)
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