Intra- and intermolecular Fe-catalyzed dicarbofunctionalization of vinyl cyclopropanes

Abstract

Design and implementation of the first (asymmetric) Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes (VCPs) with alkyl halides and aryl Grignard reagents has been realized via a mechanistically driven approach.

Radical 1,5-Chloropentafluorosulfanylation of Unactivated Vinylcyclopropanes and Transformation into α-SF5 Ketones

“…(Z)-(5-Chloro-2-(2-methoxyphenyl)pent-2-en-1-yl)pentafluoroλ 6 -sulfane (Z-3e) and (E)-(5-Chloro-2-(2-methoxyphenyl)pent-2en-1-yl)pentafluoro-λ 6 -sulfane (E-3e). Yellow oil after column chromatography with petroleum ether/ethyl acetate 20:1 (R f = 0.2), 151.5 mg (0.45 mmol), 90% yield, mixture of E/Z isomers 1.5:1.…”

“…In sharp contrast, unactivated VCPs lacking EWS less favorably form 1,3-dipoles in the presence of metal catalysts and prefer to undergo oxidative addition to form a metallacycle intermediate for subsequent annulation reactions . Unactivated VCPs, as five-carbon synthons, were explored in a number of transition-metal-catalyzed 1,5-difunctionalization reactions, e.g., Ni-catalyzed silaboration, Fe-catalyzed hydroboration, Fe-catalyzed dicarbofunctionalization, Rh-catalyzed nitrene-transfer, Cu-catalyzed cyanotrifluoromethylation, Au-catalyzed hydroamination, and Ir-catalyzed bromotrichloromethylation . In addition, an organocatalytic (C 6 F 5 ) 3 B-catalyzed ionic hydrosilylation and a visible-light-promoted hydrotrifluoromethylation have been developed.…”

Iron-catalyzed domino coupling reactions of π-systems

“…In 2020, Gutierrez and co-workers developed a Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes 14 with alkyl bromides 13 and aryl Grignard reagents 2 ( Scheme 4 ) [ 61 ]. Using sterically hindered tertiary alkyl bromides, the authors were able to favor intermolecular radical addition of the generated alkyl radical 17 to the vinylcyclopropane, outcompeting radical rebound to an aryl Fe species.…”

Enantioselective Cross‐couplings between Halide Derivatives and Organometallics by Using Iron and Cobalt Catalysts: Formation of C−C Bonds

“…In 2020, Gutierrez et al developed an enantioselective ironcatalyzed cascade radical cyclization/cross-coupling of a αchloroester with a vinylcyclopropane tether and Grignard reagents using Fe(acac) 3 (6 mol %) and BenzP* L1 (12 mol %), affording a mixture of diastereomeric 5-exo-trig radical cyclization/cross-coupling products, of which the trans,E-stereoisomer was the major diastereomer (Scheme 5). [9] By realizing a one-pot ozonolysis/NaBH 4 reduction, various chiral alcohols were obtained with low to high yields (8-82 %, over three steps) and moderate to high enantioselectivities (er = 77 : 23-90 : 10). The process tolerates a broad scope of aryl Grignard reagents, such as electron-poor and electron-rich functional groups.…”