17650-99-6Relevant academic research and scientific papers
Stereoselective Functionalization of Racemic Cyclopropylzinc Reagents via Enantiodivergent Relay Coupling
An, Lun,Tong, Fei-Fei,Zhang, Shu,Zhang, Xingang
, p. 11884 - 11892 (2020/08/06)
Efficient construction of optically pure molecules from readily available starting materials in a simple manner is an ongoing goal in asymmetric synthesis. As a straightforward route, transition-metal-catalyzed enantioconvergent coupling between widely available secondary alkyl electrophiles and organometallic nucleophiles has emerged as a powerful strategy to construct chiral center(s). However, the scope of racemic secondary alkylmetallic nucleophiles for this coupling remains limited in specific substrates because of the difficulties in stereoselective formation of the key alkylmetal intermediates. Here, we report an enantiodivergent strategy to efficiently achieve an array of synthetically useful chiral cyclopropanes, including chiral fluoroalkylated cyclopropanes and enantiomerically enriched cyclopropanes with chiral side chains, from racemic cyclopropylzinc reagents. This strategy relies on a one-pot, two-step enantiodivergent relay coupling process of the racemic cis-cyclopropylzinc reagents with two different electrophiles, which involves kinetic resolution of racemic cis-cyclopropylzinc reagents through a nickel-catalyzed enantioselective coupling with alkyl electrophiles, followed by a stereospecific relay coupling of the remaining enantiomeric cyclopropylzinc reagent with various electrophiles, to produce two types of functionalized chiral cyclopropanes with opposite configurations on the cyclopropane ring. These chiral cyclopropanes are versatile synthons for diverse transformations, rendering this strategy effective for obtaining structurally diversified molecules of medicinal interest.
Dimethylation and Hydrodechlorination of gem-Dichlorocyclopropanes with Grignard Reagents Promoted by Fe(III) or Co(II) Catalyst
Nishii, Yoshinori,Wakasugi, Kazunori,Tanabe, Yoo
, p. 66 - 69 (2007/10/03)
Reactions of gem-dichlorocyclopropanes with MeMgBr or t-BuMgCl were examined in the presence of Fe, Co, and Ni (group VIIIA, first transition series) catalysts.The Fe(dbm)3 catalyst promoted dimethylations of gem-dichlorocyclopropanes in the presence of 4
Reduction of geminal dihalocyclopropanes with ethylmagnesium bromide in the presence of tetraisopropoxytitanium
Kulinkovich,Astapovich,Masalov
, p. 1266 - 1268 (2007/10/03)
Reactions of geminal dichloro(dibromo)cyclopropanes with excess ethylmagnesium bromide in the presence of tetraisopropoxytitanium as catalyst lead to the corresponding stereoisomeric monohalocyclopropanes in good yields. A mechanism is proposed which invo
Photoinduced reduction of gem-dichlorocyclopropanes with SmI2 and benzenethiol
Ogawa, Akiya,Ohya, Syoji,Hirao, Toshikazu
, p. 275 - 276 (2007/10/03)
Upon irradiation with visible light, gem-dichlorocyclopropanes undergo reductive dechlorination with samarium diiodide and benzenethiol to provide the corresponding cyclopropanes in good yields. The reaction may proceed via the hydrogen abstraction from PhSH by cyclopropyl radicals formed in situ by the reduction with SmI2.
A simple and efficient hydrodehalogenation of 1,1-dihalocyclopropanes
Dulayymi, Juma'a R. Al,Baird, Mark S.,Bolesov, Ivan G.,Tveresovsky, Viacheslav,Rubin, Michael
, p. 8933 - 8936 (2007/10/03)
1,1-Dibromo- and 1,1-dichlorocyclopropanes are converted into the corresponding monohalocyclopropanes (as mixtures of stereoisomers where appropriate) by reaction with 1.2-1.3 mol. equiv. of ethyl magnesium bromide and a small amount of titanium isopropoxide in ether. In the presence of an excess of ethylmagnesium bromide the product from the dibromide is the non- halogenated cyclopropane. Copyright (C) 1996 Elsevier Science Ltd.
Stereoselective Carbon-Carbon Bond-Forming Reaction of 1,1-Dibromocyclopropanes via 1-Halocyclopropylzincates
Harada, Toshiro,Katsuhira, Takeshi,Hattori, Kazuhiro,Oku, Akira
, p. 2958 - 2965 (2007/10/02)
Lithium trialkylzincates react efficiently with 1,1-dibromocyclopropanes 5 to give the corresponding alkylation products 7 nonstereoselectively.The reaction proceeds through a 1,2-alkyl migration of the intermediately formed zincate carbenoid 3 in an inve
STEREOSELECTIVE REDUCTION OF gem-DICHLOROCYCLOPROPANES TO cis-MONOCHLOROCYCLOPROPANES BY LITHIUM ALUMINUM HYDRIDE IN THE PRESENCE OF TITANIUM AND ZIRCONIUM COMPLEXES
Dzhemilev, U. M.,Gaisin, R. L.,Turchin, A. A.,Tolstikov, G. A.
, p. 1845 - 1848 (2007/10/02)
A versatile stereoselective method in presented for the synthesis of cis-monochlorocyclopropanes by the reduction of dehalogenated alkyl- and aryl-gem-dichlorocyclopropanes in the presence of catalytic quantities of titanium and zirconium complexes.
EFFICIENT METHOD FOR THE SYNTHESIS OF MONOHALOCYCLOPROPANES BY REDUCTION OF GEM-DIHALOCYCLOPROPANES BY REDUCTION OF GEM-DIHALOCYCLOPROPANES WITH i-Bu2AlH IN THE PRESENCE OF Ti AND Zr COMPLEXES
Dzhemilev, U. M.,Gaisin, R. L.,Turchin, A. A.,Khalikova, N. R.,Baikova, I. P.,Tolstikov, G. A.
, p. 967 - 974 (2007/10/02)
We have investigated the reductive dehalogenation reaction of alkyl and aryl substituted gem-dihalocyclopropanes with diisobutyl aluminum hydride in the presence of catalytic amounts of titanium and zirconium complexes.As a result we propose a general method for the synthesis of substituted monohalocyclopropanes and cyclopropanes of various structures.We have also studied the stereochemistry of the reduction.
FREE RADICAL CHLORINATION AND ONE-ELECTRON OXIDATION OF ARYLCYCLOPROPANES. DESIGNER PROBES FOR CYTOCHROME P-450 HYDROXYLATION MECHANISMS
Riley, Pamela,Hanzlik, Robert P.
, p. 3015 - 3018 (2007/10/02)
Arylcyclopropyl radicals can be formed under mild conditions (phase-transfer-catalyzed chlorination) and give rise to cyclopropyl products; in contrast one-electron oxidation of arylcyclopropanes by Mn(OAc)3 leads to fragmentation of the cyclopropane ring and the formation of acyclic products.
