Cooperative activation of cyclobutanones and olefins leads to bridged ring systems by a catalytic [4 + 2] coupling.
Cooperative activation of cyclobutanones and olefins leads to bridged ring systems by a catalytic [4 + 2] coupling.
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桥环体系广泛存在于天然产物中，其成功的合成通常以分子内Diels-Alder （IMDA）反应为特征。根据二烯基序与底物其余部分的连接方式，这些反应又被细分为I型或II型imda——I型在二烯的1位连接，II型在2位连接。虽然I型IMDA的应用取得了巨大的成功，但II型IMDA可获得的分子支架受到在桥头堡位置形成sp2碳所固有的应变的限制。在这里，我们描述了一种互补的方法，通过环丁酮的C−C活化及其与烯烃的偶联来获得这些结构。各种烯烃已与环丁酮偶联，以提供一系列桥骨架。产品的酮基为下游功能化提供了方便的处理。
Bridged-ring systems are widely found in natural products and successful syntheses of them frequently feature intramolecular Diels-Alder (IMDA) reactions. These reactions are subclassified as either type I or type II IMDAs depending on how the diene motif is tethered to the rest of the substrate - type I are tethered at the 1-position of the diene and type II at the 2-position. While the type I IMDA has been used to great success, the molecular scaffolds accessible by type II IMDAs are limited by the strain inherent in the formation of a sp2-carbon at a bridgehead position. Here, we describe a complementary approach that provides access to these structures through the C−C activation of cyclobutanones and their coupling with olefins. Various alkenes have been coupled with cyclobutanones to provide a range of bridged skeletons. The ketone group of the products serves as a convenient handle for downstream functionalization.
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影响因子：
5.2
作者：
Cheng, Xiayun;Waters, Stephen P.
通讯作者：
Waters, Stephen P.
影响因子：
46.2
作者：
CRAIG, D
通讯作者：
CRAIG, D
影响因子：
15
作者：
Jun, CH;Lee, H;Lim, SG
通讯作者：
Lim, SG
影响因子：
15
作者：
Murakami, M;Itahashi, T;Ito, Y
通讯作者：
Ito, Y
影响因子：
7.3
作者：
Breining, Scott R.;Melvin, Matt;Yohannes, Daniel
通讯作者：
Yohannes, Daniel