The trifluoromethylcarbene (:CHCF3) was found to be conveniently generated from (2,2,2-trifluoroethyl)diphenyl-sulfonium triflate (Ph2S+CH2CF3–OTf), which was successfully applied in Fe-catalyzed cyclopropanation of olefins, giving the corresponding trifluoromethylated cyclopropanes in high yields.
Iron-Catalyzed Cyclopropanation with Trifluoroethylamine Hydrochloride and Olefins in Aqueous Media: In Situ Generation of Trifluoromethyl Diazomethane
作者:Bill Morandi、Erick M. Carreira
DOI:10.1002/anie.200905573
日期:2010.1.25
Let's avoid the risk! The title transformation has been developed for the synthesis of trifluoromethyl‐substituted cyclopropane derivatives (see scheme). It avoids the preparation of trifluoromethyldiazomethane and merges a number of areas: water as a reaction medium, iron catalysis, and access to reactive intermediates under operationally safe conditions.
Highly Diastereo- and Enantioselective Synthesis of Trifluoromethyl-Substituted Cyclopropanes via Myoglobin-Catalyzed Transfer of Trifluoromethylcarbene
catalysts expressed in bacterial cells. This approach was successfully applied to afford a variety of trans-1-trifluoromethyl-2-arylcyclopropanes in high yields (61-99%) and excellent diastereo- and enantioselectivity (97-99.9% de and ee). Furthermore, mirror-image forms of these products could be obtained using myoglobin variants featuring stereodivergent selectivity. These reactions provide a convenient
我们报告了一种在 2-重氮-1,1,1-三氟乙烷 (CF3CHN2) 作为卡宾供体存在下,通过肌红蛋白催化的烯烃环丙烷化反应不对称合成三氟甲基取代的环丙烷的有效策略。这些转化是使用两室装置实现的,其中异位产生的气态 CF3CHN2 由细菌细胞中表达的工程肌红蛋白催化剂进行处理。该方法已成功应用于提供各种反式-1-三氟甲基-2-芳基环丙烷,收率高(61-99%),并且具有优异的非对映和对映选择性(97-99.9% de 和 ee)。此外,可以使用具有立体发散选择性的肌红蛋白变体获得这些产物的镜像形式。这些反应为立体选择性合成对药物化学和药物发现具有高价值的关键氟化结构单元提供了便捷有效的生物催化途径。这项工作扩大了通过金属蛋白催化剂实现的卡宾介导的转化范围,并引入了在生物催化卡宾转移反应中利用气态和/或难以处理的卡宾供体试剂的潜在通用策略。