Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China.
Org Lett. 2023 Mar 10;25(9):1420-1424. doi: 10.1021/acs.orglett.3c00139. Epub 2023 Feb 27.
The iron-catalyzed coupling of alkenes and enones through allylic C(sp)-H functionalization is reported. This redox-neutral process employs a cyclopentadienyliron(II) dicarbonyl catalyst and simple alkene substrates to generate catalytic allyliron intermediates for 1,4-addition to chalcones and other conjugated enones. The use of 2,4,6-collidine as the base and a combination of triisopropylsilyl triflate and LiNTf as Lewis acids was found to facilitate this transformation under mild, functional group-tolerant conditions. Both electronically unactivated alkenes as well as allylbenzene derivatives could be employed as pronucleophilic coupling partners, as could a range of enones bearing electronically varied substituents.
报道了通过烯丙基 C(sp^3)-H 功能化实现烯烃和烯酮的铁催化偶联。该氧化还原中性过程采用环戊二烯基二羰基铁(II)催化剂和简单的烯烃底物，生成催化烯丙基铁中间体，用于对查尔酮和其他共轭烯酮进行 1,4-加成。发现使用 2,4,6-三吡啶和三氟甲磺酸三异丙酯与 LiNTf 的组合作为路易斯酸，并在温和、官能团耐受的条件下，有利于这种转化。未活化的烯烃以及烯丙基苯衍生物都可以作为亲核性偶联试剂使用，一系列带有电子变化取代基的烯酮也可以使用。
