Ying Jinbiao, Liu Ting, Liu Yunyun, Wan Jie-Ping
Key Lab of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, P. R. China.
Org Lett. 2022 Apr 1;24(12):2404-2408. doi: 10.1021/acs.orglett.2c00671. Epub 2022 Mar 18.
A practical method for the synthesis of 2,2-difluorinated 2,3-dihydrofurans has been established via the [4 + 1] annulation of enaminones and BrCFCOEt with NaCO promotion. This new protocol does not employ any transition metal reagent and enables the annulative difluoromethylation by the partial cleavage of the C═C double bond. In addition, the further treatment with hydrochloric acid in one pot leads to β-keto enoic acids (4-oxo-2-butenoic acids) via a formal enaminone C-N carboxylation.
通过烯胺酮与BrCFCOEt在NaCO促进下的[4 + 1]环化反应，建立了一种合成2,2-二氟代-2,3-二氢呋喃的实用方法。该新方法不使用任何过渡金属试剂，通过C═C双键的部分裂解实现环化二氟甲基化。此外，一锅法中用盐酸进一步处理可通过烯胺酮的C-N羧化反应生成β-酮烯酸（4-氧代-2-丁烯酸）。
