Enantioselective Cobalt‐Catalyzed Preparation of Trifluoromethyl‐Substituted Cyclopropanes

Abstract

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

Diazo ester insertion in NH bonds of amino acid derivatives and insulin catalyzed by water-soluble iron and ruthenium porphyrin complexes (FeTSPPCl) as application of carbenoid transfer in aqueous media

“…Aviv and Gross [18] also reported intermolecular N H insertion of anilines in water/THF catalyzed by myoglobin. Although, there are many examples showing that 5,10,15,20-tetrakis-(4-sulfonato-phenyl)-porphyrin-iron(III) chloride is a versatile water-soluble catalyst for oxidations in organic syntheses [22] and few other reactions [23,24], its use for carbenoid transfer in water seems to be neglected [25]. Comparative evaluation of reactivity for N-H insertion of different diazo derivatives with iron and ruthenium porphyrins will also be described.…”

Highly Diastereo- and Enantioselective Synthesis of Trifluoromethyl-Substituted Cyclopropanes via Myoglobin-Catalyzed Transfer of Trifluoromethylcarbene

“…4 To date, however, only a few studies have addressed the problem of developing enantioselective variants of these transformations. 4a,5 In a first report, Simmoneaux and coworkers described the use of chiral metalloporphyrins for the asymmetric cyclopropanation of styrenes in the presence of 2-diazo-1,1,1-trifluoroethane, but only moderate enantioselectivity (30–79% ee ) was observed using this system. 4a Higher selectivity was more recently achieved in similar reactions using Co(III)-salen complexes by Carreira and coworkers.…”

Iron Catalysis in Synthetic Chemistry

“…Trifluoromethylated cyclopropanes are important compounds in drug delivery (45), though very few synthetic methods were reported for their preparation. Carreira and co-workers (46,47) recently reported potentially applicable methods for the synthesis of trifluoromethylated cyclopropanes by using trifluoroethylamine hydrochloride as the carbene source. Tandem cyclopropanation occurred in the presence of 3 mol% Fe(TPP)Cl (24) and saturated NaNO 2 solution to generate carbene.…”

“…Sharpless epoxidation of allylic alcohol and Katsuki-Jacobsen asymmetric epoxidation are historically significant in the development of epoxidation chemistry (126). First, ironcatalyzed epoxidation was reported in 2001 by Jacobsen and co-workers (127) with Fe-mep (46) in the presence of a catalytic amount of acetic acid (Scheme 102). Acetic acid plays a key role in order to form an iron-μ-oxo carboxylate bridged iron complex, which was most likely to be the active species as proposed by Jacobsen and co-workers (127).…”