环加成
环丙烷
非对映体
化学
烯烃
立体选择性
原位
三氟甲基
组合化学
有机化学
立体化学
戒指(化学)
催化作用
烷基
作者
Pavel S. Nosik,Yaroslav V. Mykhalchuk,Oleksandr S. Liashuk,Andriy Kysil,Oleksandr O. Grygorenko
标识
DOI:10.1002/slct.202302143
摘要
Abstract A metal‐free two‐step approach for the synthesis of trisubstituted CF 3 ‐cyclopropanes is reported. The method involves [3+2] cycloaddition of electron‐poor alkenes and in situ generated 2,2,2‐trifluorodiazoethane, followed by N 2 extrusion from intermediate pyrazolines. The protocol offers good yields of 39–90 %, is compatible with a range of functional groups, and enables multigram preparation on a scale of up to 30 grams. The method is limited by 1,1‐disubstituted alkene partners, and both cycloaddition and N 2 extrusion steps are not stereoselective, resulting in ca. 1 : 1 mixtures of diastereomers. Nevertheless, the stereoisomeric mixtures can be separated at further steps by column chromatography or crystallization, thus allowing to produce diverse diastereopure (poly)functionalized CF 3 ‐cyclopropane building blocks relevant to drug discovery.
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