Enantioselective Cobalt-Catalyzed Preparation of Trifluoromethyl-Substituted Cyclopropanes
作者:Bill Morandi、Brian Mariampillai、Erick M. Carreira
DOI:10.1002/anie.201004269
日期:2011.2.1
Easy access on water: A cobalt‐catalyzed asymmetric preparation of trifluoromethylcyclopropanes has been developed that yields high enantioselectivities with a broad range of styrene substrates (see scheme). The reaction presents a new access to enantioenriched CF3‐containing building blocks.
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。
Iron(III)-based metalloradical catalysis for asymmetric cyclopropanation via a stepwise radical mechanism
作者:Wan-Chen Cindy Lee、Duo-Sheng Wang、Yiling Zhu、X. Peter Zhang
DOI:10.1038/s41557-023-01317-8
日期:2023.11
initial application for asymmetric radical transformations. Specifically, we report that five-coordinate iron(III) complexes of porphyrins with an axial ligand, which represent another family of stable 15e-metalloradicals with a d5 configuration, are potent metalloradical catalysts for olefin cyclopropanation with different classes of diazocompounds via a stepwise radical mechanism. This work lays a foundation
Synthesis of Ring-Fluorinated Thiophene Derivatives Based on Single C–F Bond Activation of CF<sub>3</sub>-Cyclopropanes: Sulfanylation and 5-<i>endo</i>-<i>trig</i> Cyclization
作者:Kohei Fuchibe、Tatsuki Fushihara、Junji Ichikawa
DOI:10.1021/acs.orglett.0c00385
日期:2020.3.20
The treatment of CF3-bearing cyclopropanes with Et2AlCl generated stabilized difluorocarbocations, which underwent a nucleophilic addition of thiocarboxylic acids or thiols. The sulfur functionality was introduced at the position δ to the fluorine substituents in a regioselective manner (single activation of CF3-cyclopropanes). The formed 1,1-difluoro-1-alkenes underwent successive deesterification/5-endo-trig
vinyl amines, vinyl carbamates and dienes, was achieved by using Ru(II)–Pheox catalysts. This catalytic system can function at a low catalyst loading (3 mol%) compared with those reported previously, and the desired cyclopropane products are obtained in high yields with excellent diastereoselectivity (up to >99 : 1) and enantioselectivity (up to 97% ee).