68907-41-5Relevant academic research and scientific papers
Stereoselective Functionalization of Racemic Cyclopropylzinc Reagents via Enantiodivergent Relay Coupling
An, Lun,Tong, Fei-Fei,Zhang, Shu,Zhang, Xingang
supporting information, 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.
Rhodium Porphyrin Catalyzed Regioselective Transfer Hydrogenolysis of C-C σ-Bonds in Cyclopropanes with iPrOH
Chen, Chen,Feng, Shiyu,Chan, Kin Shing
supporting information, p. 2582 - 2589 (2019/07/02)
A new rhodium porphyrin catalyzed regioselective transfer hydrogenolysis of both activated and unactivated cyclopropanes employing iPrOH as the hydrogen source was discovered. The reaction mechanism for the C-C σ-bond activation of cyclopropanes was identified through an initial radical substitution with rhodium(II) metalloporphyrin radical to give a rhodium porphyrin alkyl, followed by hydrogenolysis with iPrOH to give the corresponding acyclic alkanes and regenerate rhodium(II) metalloporphyrin radical.
Tris(trimethylsilyl)silane-mediated reductive decyanation and cyano transfer reactions of malononitriles
Kawamoto, Takuji,Shimaya, Yudai,Curran, Dennis P.,Kamimura, Akio
, p. 573 - 575 (2018/04/12)
Reductive decyanation reactions of malononitriles were achieved with tris(trimethylsilyl)silane as a radical mediator. The reaction proceeds via a radical chain mechanism involving a silyl radical addition to the malononitrile to form an imidoyl radical followed by α-cleavage to give a silyl isocyanide and an α-cyano radical. The reaction of a 3-butenyl-substituted malononitrile afforded a decyano/cyanosilylation product in good yield through 1,4-cyano transfer.
Towards nitrile-substituted cyclopropanes-a slow-release protocol for safe and scalable applications of diazo acetonitrile
Hock, Katharina J.,Spitzner, Robin,Koenigs, Rene M.
, p. 2118 - 2122 (2017/07/24)
Diazo acetonitrile has long been neglected despite its high value in organic synthesis due to a high risk of explosions. Herein, we report our efforts towards the transient and safe generation of this diazo compound, its applications in iron catalyzed cyclopropanation and cyclopropenation reactions and the gram-scale synthesis of cyclopropyl nitriles.
Olefin cyclopropanation by a sequential atom-transfer radical addition and dechlorination in the presence of a ruthenium catalyst
Thommes, Katrin,Kiefer, Gregor,Scopelliti, Rosario,Severin, Kay
supporting information; experimental part, p. 8115 - 8119 (2010/01/16)
Without diazo: The reductive coupling of olefins with dichloro compounds in the presence of a ruthenium catalyst and magnesium gives cyclopropanes in good yield (see scheme).
Macroporous chiral ruthenium porphyrin polymers: A new solid-phase material used as a device for catalytic asymmetric carbene transfer
Ferrand, Yann,Le Maux, Paul,Simonneaux, Gerard
, p. 3829 - 3836 (2007/10/03)
A chiral ruthenium porphyrin complex, functionalized with four vinyl groups, has been polymerized with styrene, divinylbenzene (or ethylene glycol dimethacrylate) to obtain supported ruthenium complexes. The asymmetric addition of ethyl diazoacetate (or d
A novel approach to enantiopure cyclopropane compounds from biotransformation of nitriles
Wang, Mei-Xiang,Feng, Guo-Qiang
, p. 1575 - 1583 (2007/10/03)
Rhodococcus sp. AJ270, a powerful and versatile nitrile hydratase/amidase containing microbial whole-cell system, catalyzed the enantioselective hydrolysis of both racemic trans- and cis-2-arylcyclopropanecarbonitriles to afford the corresponding amides and acids with enantiomeric excesses as high as >99%. The reaction rate and enantioselectivity observed for both nitrile hydratase and amidase were also strongly dependent upon the nature of the substituent and substitution pattern on the benzene ring of the substrates. The application of and the advantages of biotransformation of nitriles were demonstrated by preparing (1S,2R)-2-phenylcyclopropylamine and (1R,2R)-2-phenylcyclopropylmethylamine through facile and straightforward chemical manipulations of (1S,2S)-2-phenylcyclopropanecarboxylic acid and (1R,2R)-2-phenylcyclopropanecarboxamide, respectively.
VIBRATIONAL CIRCULAR DICHROISM OF OPTICALLY ACTIVE CYCLOPROPANES. 3. TRANS-2-PHENYLCYCLOPROPANECARBOXYLIC ACID DERIVATIVES AND RELATED COMPOUNDS
Yasui, Sritana C.,Keiderling, Timothy A.
, p. 2311 - 2320 (2007/10/02)
Vibrational circular dichroism (VCD) data are presented for a series of (1R,2R)-trans-2-phenyl-1-(R-substituted)cyclopropanes where R=COOCH3, COOCD3, COOH, CONH2, COCl, CN, CH2OH, CD2OD, CH3, CD3, and NH2 (1S,2R).In addition, VCD for (1S,2S)-1-phenylpropylene oxide is presented for comparison.These data can be correlated to show certain characteristic, structure-indicating transitions common to all of the molecules.This is particularly true in the cyclopropane C-H stretching bands in the near-IR and less so of CH2 deformations and ring modes in the mid-IR.To elucidate these comparisons it is necessary to interpret the frerquency shifts of the characteristic bands as the substituent is varied.The range of compounds studied permits such an analysis for certain characteristic modes.The results for monocarbonyl and-cyano substitution further explain the presence and absence, respectively, of coupled oscillator VCD in the corresponding symmetrically disubstituted cyclopropyl compounds.
Steric Retard of Internal Rotation in 1-Carbomethoxy-1,2-diphenylcyclopropane
Doering, W. von E.,Robertson, L. R.,Ewing, E. E.
, p. 4280 - 4286 (2007/10/02)
The high preference (RA = 13) found by Chmurny and Cram for internal rotation of the hydrogen-phenyl carbon bond over the carbomethoxy-phenyl carbon bond in 1-carbomethoxy-1,2-diphenylcyclopropane appears to originate in a steric effect.There b
