Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University , 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530, Japan.
Org Lett. 2017 Nov 17;19(22):6104-6107. doi: 10.1021/acs.orglett.7b02956. Epub 2017 Oct 30.
The combination of diiodomethylboronate ester, CrCl with TMEDA promoted borylcyclopropanation of unactivated alkenes under mild conditions. Compared with the typical Simmons-Smith cyclopropanation, the current protocol offers the following advantages: (1) the reaction proceeds stereoselectively with disubstituted alkenes even without hydroxy or alkoxy groups; (2) both electron-rich and electron-deficient alkenes can be applicable; and (3) the reaction does not require potentially flammable alkylzinc. These unique reactivity features result from the steric and electronic nature of the gem-dichromiomethane intermediates.
二碘甲基硼酸酯、CrCl 和 TMEDA 的组合在温和条件下促进了未活化烯烃的硼环丙烷化。与典型的 Simmons-Smith 环丙烷化反应相比，该方案具有以下优点：（1）反应具有立体选择性，即使没有羟基或烷氧基取代基，二取代烯烃也能进行反应；（2）富电子和缺电子烯烃都适用；（3）反应不需要潜在易燃的烷基锌。这些独特的反应性特征源于偕二铬甲烷中间体的空间和电子性质。
