Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
Angew Chem Int Ed Engl. 2018 Oct 15;57(42):13902-13906. doi: 10.1002/anie.201807542. Epub 2018 Sep 25.
Dimethylcyclopropanes are valuable synthetic targets that are challenging to access in high yield using Zn carbenoid reagents. Herein, we describe a cobalt-catalyzed variant of the Simmons-Smith reaction that enables the efficient dimethylcyclopropanation of 1,3-dienes using a Me CCl /Zn reagent mixture. The reactions proceed with high regioselectivity based on the substitution pattern of the 1,3-diene. The products are vinylcyclopropanes, which serve as substrates for transition-metal-catalyzed ring-opening reactions, including 1,3-rearrangement and [5+2] cycloaddition. Preliminary studies indicate that moderately activated monoalkenes are also amenable to dimethylcyclopropanation under the conditions of cobalt catalysis.
二甲基环丙烷是有价值的合成目标，但使用 Zn 卡宾试剂难以高产率地获得。在此，我们描述了 Simmons-Smith 反应的钴催化变体，该变体可使用 Me CCl/Zn 试剂混合物有效地对 1,3-二烯进行二甲基环丙烷化。反应具有高的区域选择性，这取决于 1,3-二烯的取代模式。产物是乙烯基环丙烷，可作为过渡金属催化开环反应的底物，包括 1,3-重排和 [5+2]环加成。初步研究表明，在钴催化条件下，中等活化的单烯烃也适合二甲基环丙烷化。
