- Synthesis of Difluorinated Heterocyclics through Metal-Free [8+1] and [4+1] Cycloaddition of Difluorocarbene
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With Ph3P+CF2COO- or TMSCF2Br as the difluorocarbene sources, a facile metal-free cycloaddition between heteroconjugated alkenes and difluorocarbene was developed for the highly convergent synthesis of novel difluorinated heterocyclics, including gem-difluorinated azetidines and 2,3-dihydrobenzofurans. The cycloaddition features high reactivity and regioselectivity, as well as good tolerance of various electron-donating or electron-withdrawing substituents on azaheptafulvenes and o-quinone methides.
- Jia, Yimin,Yuan, Yuan,Huang, Jinfeng,Jiang, Zhong-Xing,Yang, Zhigang
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- [4u202f+u202f1] Cyclization of benzohydrazide and ClCF2COONa towards 1,3,4-oxadiazoles and 1,3,4-oxadiazoles-d5
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A facile synthesis of 1,3,4-oxadiazoles and 1,3,4-oxadiazoles-d5 via [4 + 1] cyclization of ClCF2COONa with non-amine compounds containing amino groups is developed. Of note, this is the first time that halofluorinated compounds are used as C1 synthon to construct deuterated nitrogen-heterocyclic compounds. The current protocol features simple operation, readily accessible raw materials, wide substrate scope and valuable products
- Li, Xin,Mu, Shiqiang,Song, Qiuling,Wang, Ya
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supporting information
(2021/09/20)
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- Transition metal-free assembly of 1,3,5-triazines using ethyl bromodifluoroacetate as C1 source
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An efficient transition metal-free annulation of amidine with ethyl bromodifluoroacetate to access 2,4-disubstituted-1,3,5-triazines is firstly presented. The desired symmetric and unsymmetric 2,4-disubstituted-1,3,5-triazines were obtained in decent yields via multiple C-N bond formation, in which ethyl bromodifluoroacetate is harnessed as a unique C1 synthon via quadruple cleavage. This reaction is transition metal-free, oxidant-free and simple in operation, and only lowly toxic inorganic wastes are generated.
- Yu, Xiaoxia,Zhou, Yao,Ma, Xingxing,Song, Qiuling
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p. 8079 - 8082
(2019/07/15)
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- An efficient method for the N-formylation of amines under catalyst- and additive-free conditions
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A simple catalyst- and additive-free method for the N-formylation of amines has been developed. The advantages of this protocol include a wide range of functional group tolerance, high efficiency and a lack of required extra promoters under mild conditions. This convenient strategy will provide a facile synthesis towards N-formamide natural products and pharmaceutical derivatives. A mechanism that involves difluorocarbene is proposed for this reaction.
- Xu, Zhuo-Wei,Xu, Wen-Yi,Pei, Xiao-Jun,Tang, Fei,Feng, Yi-Si
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supporting information
p. 1254 - 1258
(2019/04/10)
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