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.
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).
Synthesis of <i>trans</i>-2-(Trifluoromethyl)cyclopropanes via Suzuki Reactions with an <i>N</i>-Methyliminodiacetic Acid Boronate
作者:Matthew A. J. Duncton、Rajinder Singh
DOI:10.1021/ol401636d
日期:2013.9.6
trans-2-(Trifluoromethyl)cyclopropylboronic acid N-methyliminodiacetic acid (MIDA) ester 5 was synthesized as a pure diastereomer from vinylboronic acid MIDA ester and (trifluoromethyl)diazomethane in a single step. An X-ray study confirmed the trans-stereochemistry around the cyclopropyl ring. Use of 5 in Suzuki reactions, with a variety of aryl or heteroaryl coupling partners, provided trans-2-(
Asymmetric Synthesis of Trifluoromethylphenyl Cyclopropanes Catalyzed by Chiral Metalloporphyrins
作者:Gérard Simonneaux、Paul Le Maux、Sandrine Juillard
DOI:10.1055/s-2006-926451
日期:2006.5
The asymmetric addition of 2,2,2-trifluorodiazoethane to styrene derivatives to give optically active trifluoromethylphenyl cyclopropanes (ee values up to 69%) was carried out by using chiral iron and ruthenium porphyrins as homogeneous and heterogeneous catalysts.
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.