Zhang Jing, Xiong Daokai, Jiang Zhiwei, Chen Shuaiting, Huang Guo-Bo, Li Jinshan, Wang Zhiming, Yang Jianguo
Advanced Research Institute and School of Pharmaceutical Science, Taizhou University, Jiaojiang, Zhejiang 318000, P. R. China.
Hainan Provincial Key Lab of Fine Chem, School of Chemistry and Chemical Engineering, Hainan University, Haikou, Hainan 570228, P. R. China.
Org Lett. 2024 Feb 23;26(7):1447-1451. doi: 10.1021/acs.orglett.4c00078. Epub 2024 Feb 14.
Difluoroenoxysilane, a commonly used difluoroallylating reagent, has attracted considerable attention in recent years. However, its application in the annulation reaction for the construction of fluorinated heterocyclic compounds remains relatively limited. Presented here is the Brønsted acid-catalyzed efficient formal [4 + 2] annulation of difluoroenoxysilanes with α-cyano chalcones. The developed protocol demonstrates tolerance to various substituents under mild reaction conditions, providing a reliable approach to construct -difluoro-3,4-dihydro-2-pyrans in good to excellent yields with high diastereoselectivities.
二氟烯氧基硅烷是一种常用的二氟烯丙基化试剂，近年来受到了广泛关注。然而，其在构建含氟杂环化合物的环化反应中的应用仍然相对有限。本文报道了在布朗斯特酸催化下，二氟烯氧基硅烷与α-氰基查尔酮的高效形式[4 + 2]环化反应。所开发的方法在温和的反应条件下对各种取代基具有耐受性，为构建二氟-3,4-二氢-2-吡喃提供了一种可靠的方法，产率良好至优异，非对映选择性高。
