Under specific high concentration, high temperature conditions, methyl 2,2-difluoro-2-(fluorosulfonyl)acetate (MDFA) has been found to act as a very efficient source of difluorocarbene, exhibiting carbene reactivity characteristics comparable to those exhibited by trimethylsilyl 2,2-difluoro-2-(fluorosulfonyl)acetate (TFDA). For example, in reaction with highly unreactive n-butyl acrylate and using only 2 equiv of MDFA, a yield of 76% of difluorocyclopropane product was obtained after 2 days.

中文翻译：

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2,2-二氟-2-（氟磺酰基）乙酸甲酯，一种具有与三甲基2,2-二氟-2-（氟磺酰基）乙酸酯相当的反应性的二氟卡宾试剂

在特定的高浓度，高温条件下，已发现2,2-二氟-2-（氟磺酰基）乙酸甲酯（MDFA）是非常有效的二氟卡宾来源，其卡宾反应性特征可与三甲基甲硅烷基2媲美。 2-二氟-2-（氟磺酰基）乙酸酯（TFDA）。例如，与高度不活泼的丙烯酸正丁酯反应，仅使用2当量的MDFA，在2天后获得76％的二氟环丙烷产物。