- Ni-Catalyzed [8+3] cycloaddition of tropones with 1,1-cyclopropanediesters
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A variety of cycloheptapyrane derivatives were prepared via Ni-catalyzed formal [8+3] cycloaddition of tropones with 1,1-cyclopropanediesters. The asymmetric version of the process can be achieved using either an enantiomerically enriched cyclopropane as the starting material or a racemic cyclopropane and a chiral Lewis acid.
- Tejero, Ruben,Ponce, Alberto,Adrio, Javier,Carretero, Juan C.
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- Stable dicarbonylcarbene complexes of bis(oxazolinyl)pyridine ruthenium and osmium
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The reaction of RuCl2(pybox)(C2H4) [pybox = 2,6-bis(oxazolinyl)pyridine] 1 and OsCl2(pybox)(propylene) 6 with dimethyl diazomalonate gave stable dicarbonylcarbene complexes 9 and 10 in 92% and 59% yields, respectively. The carbene moiety of 9 proved to be almost parallel in the Cl-Ru-Cl plane by 10-12° and perpendicular to the pybox plane by X-ray analysis. The transfer of the carbene moiety of 9 to styrene could be observed at 110°C to give the corresponding cyclopropane 15 but in a low yield (11%) with asymmetric induction in 36% ee.
- Nishiyama, Hisao,Aoki, Katsuyuki,Itoh, Hirofumi,Iwamura, Taichiro,Sakata, Naoya,Kurihara, Osamu,Motoyama, Yukihiro
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- (3+2)-Cycloaddition of Donor-Acceptor Cyclopropanes with Thiocyanate: A Facile and Efficient Synthesis of 2-Amino-4,5-dihydrothiophenes
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An easy and efficient route to obtain 2-amino-4,5-dihydrothiophenes is presented. A formal (3+2)-cycloaddition of donor-acceptor cyclopropanes and ammonium thiocyanate catalyzed by Yb(OTf) 3delivers the desired products in good to excellent yields. A broad range of functional groups is tolerated during this process.
- Jacob, Anu,Barkawitz, Philip,Andreev, Ivan A.,Ratmanova, Nina K.,Trushkov, Igor V.,Werz, Daniel B.
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supporting information
p. 901 - 904
(2021/03/17)
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- Synthesis of Substituted β-Styrylmalonates by Sequential Isomerization of 2-Arylcyclopropane-1,1-dicarboxylates and (2-Arylethylidene)malonates
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A method has been developed for the synthesis of substituted β-styrylmalonates by conversion of 2-arylcyclopropane-1,1-dicarboxylates (ACDCs) in the presence of gallium trichloride into the corresponding- 1,2-zwitterionic intermediates or (2-arylethyl-idene)malonates, followed by treatment with pyridine at room temperature leading to an isomerization of the emerging double bond. This method allows one to expand these reactions to include ACDCs with acceptor substituents at the aromatic ring.
- Borisov, Denis D.,Chermashentsev, Grigorii R.,Novikov, Roman A.,Tomilov, Yury V.
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supporting information
p. 2253 - 2259
(2021/03/04)
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- Electricity Driven 1,3-Oxohydroxylation of Donor-Acceptor Cyclopropanes: a Mild and Straightforward Access to β-Hydroxy Ketones
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An unprecedented external oxidant-free electrochemical protocol for 1, 3-oxohydroxylation of donor-acceptor cyclopropane is disclosed. The strategy encompasses the activation of the labile π-electron cloud of the aryl ring to cleave the strained Csp3?Csp3 bond of cyclopropane to afford the β-hydroxy ketones via insertion of molecular oxygen. More significantly, based on the detailed mechanistic investigations and cyclic voltammetry experiments, a plausible mechanism is proposed.
- Banerjee, Prabal,Maajid Taily, Irshad,Saha, Debarshi
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p. 5053 - 5057
(2021/09/30)
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- (3 + 2)-Cycloaddition of Donor-Acceptor Cyclopropanes with Selenocyanate: Synthesis of Dihydroselenophenes and Selenophenes
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We present a Lewis-acid-catalyzed (3 + 2)-cycloaddition of donor-acceptor cyclopropanes and selenocyanate (as its tetramethylammonium salt) for the synthesis of dihydroselenophenes. The transformation proceeded with moderate to excellent yields and showed a high functional group tolerance. Further oxidation using DDQ delivered selenophenes.
- Jacob, Anu,Jones, Peter G.,Werz, Daniel B.
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supporting information
(2020/11/13)
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- Blue LED Irradiation of Iodonium Ylides Gives Diradical Intermediates for Efficient Metal-free Cyclopropanation with Alkenes
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A facile and highly chemoselective synthesis of doubly activated cyclopropanes is reported where mixtures of alkenes and β-dicarbonyl-derived iodonium ylides are irradiated with light from blue LEDs. This metal-free synthesis gives cyclopropanes in yields
- Chidley, Tristan,Jameel, Islam,Rizwan, Shafa,Peixoto, Philippe A.,Pouységu, Laurent,Quideau, Stéphane,Hopkins, W. Scott,Murphy, Graham K.
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supporting information
p. 16959 - 16965
(2019/11/11)
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- Stereospecific copper(II)-catalyzed tandem ring opening/oxidative alkylation of donor-acceptor cyclopropanes with hydrazones: Synthesis of tetrahydropyridazines
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Aerobic copper(II)-catalyzed tandem ring opening and oxidative C-H alkylation of donor-acceptor cyclopropanes with bisaryl hydrazones is accomplished to produce tetrahydropyridazines, in which copper(II) plays dual role as a Lewis acid as well as redox catalyst. The reaction is stereospecific, and optically active cyclopropanes can be reacted with high optical purities (89-98% enantiomeric excess). The substrate scope, functional group tolerance, dual role of the copper(II) catalyst, and the use of air as an oxidant are the important practical features. A product bearing a 3-bromoaryl group can be subjected to Pd-catalyzed Suzuki coupling with boronic acid in high yield.
- Mishra, Manmath,De, Pinaki Bhusan,Pradhan, Sourav,Punniyamurthy, Tharmalingam
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p. 10901 - 10910
(2019/09/13)
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- Formal Insertion of Thioketenes into Donor-Acceptor Cyclopropanes by Lewis Acid Catalysis
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Donor-acceptor cyclopropanes were reacted under Lewis acid catalysis with 3-thioxocyclobutanones as surrogates for disubstituted thioketenes. A broad scope of 2-substituted tetrahydrothiophenes with a semicyclic double bond was obtained under mild conditions with high functional group tolerance and in excellent yield. A sequence of a formal [3 + 2]-cycloaddition followed by the subsequent release of disubstituted ketene is postulated as the mechanism.
- Augustin, André U.,Busse, Marius,Jones, Peter G.,Werz, Daniel B.
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supporting information
p. 820 - 823
(2018/02/10)
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- Synthesis of five-membered cyclic nitrones based on the Lewis acid-catalysed [3+2]-annulation reaction of donor-acceptor cyclopropanes with 1,4,2-dioxazoles
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A novel synthesis of five-membered cyclic nitrones has been developed based on the Lewis acid-catalysed [3+2]-annulation reaction of D-A cyclopropanes with 1,4,2-dioxazoles. Broad substrate scope and generally good yield make this reaction useful in the p
- Wang, Zhe-Hao,Zhang, Huan-Huan,Xu, Peng-Fei,Luo, Yong-Chun
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p. 10128 - 10131
(2018/09/13)
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- Nucleophilic Ring Opening of Donor-Acceptor Cyclopropanes Catalyzed by a Br?nsted Acid in Hexafluoroisopropanol
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A general, Br?nsted acid catalyzed method for the room temperature, nucleophilic ring opening of donor-acceptor cyclopropanes in fluorinated alcohol solvent, HFIP, is described. Salient features of this method include an expanded cyclopropane scope, including those bearing single keto-acceptor groups and those bearing electron-deficient aryl groups. Notably, the catalytic system proved amenable to a wide range of nucleophiles including arenes, indoles, azides, diketones, and alcohols.
- Richmond, Edward,Vukovi?, Vuk D.,Moran, Joseph
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p. 574 - 577
(2018/02/10)
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- An Expeditious Route to trans-Configured Tetrahydrothiophenes Enabled by Fe(OTf)3-Catalyzed [3+2] Cycloaddition of Donor–Acceptor Cyclopropanes with Thionoesters
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A synthetic route to trans-configured tetrahydrothiophenes (THTs) through Fe(OTf)3-promoted [3+2] cycloaddition of donor–acceptor cyclopropanes with thionoesters was developed. The cycloaddition proceeded in high yield with high diastereoselectivity, affording transient α-alkoxy THTs. Not only aromatic and aliphatic thionoesters, but also thionolactone were applicable to the present iron catalysis. Further transformation of the S,O-ketal functionality of the product was achieved in a highly trans diastereoselective manner. Moreover, the utility of our methodology was clearly demonstrated by the synthesis of enantioenriched trans-configured THTs.
- Matsumoto, Yohei,Nakatake, Daiki,Yazaki, Ryo,Ohshima, Takashi
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p. 6062 - 6066
(2018/03/28)
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- Metal-free intermolecular cyclopropanation between alkenes and iodonium ylides mediated by PhI(OAc)2·Bu4NI
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A rapid, mild and metal-free intermolecular cyclopropanation between iodonium ylides and alkene-containing substrates mediated by PhI(OAc)2·Bu4NI is reported. Iodonium ylides of cyclic and acyclic 1,3-dicarbonyls were reacted with a variety of mono-, di-, tri- and tetra-substituted alkenes of various structural types to give 29 cyclopropanes in up to 97% yield.
- Tao, Jason,Estrada, Carl D.,Murphy, Graham K.
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supporting information
p. 9004 - 9007
(2017/08/15)
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- Catalytic Hydrogenolysis of Enantioenriched Donor–Acceptor Cyclopropanes Using H2 and Palladium on Charcoal
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The hydrogenolysis of enantioenriched donor–acceptor (D–A) cyclopropanes using H2 (1 atm) and a catalytic amount of palladium on charcoal gave trans-α-alkoxycarbonyl-β-benzyl-γ-lactones or β-substituted γ-aryl-α,α-diesters with high enantiomeric excess. The reaction was also used as a key step in the asymmetric total synthesis of yatein with high ee and excellent dr. This demonstrates the utility of this new protocol for the asymmetric synthesis of trans-α,β-disubstituted γ-butyrolactones. D–A cyclopropanes containing electron-withdrawing groups at the β-position were not susceptible to hydrogenolysis under these conditions. The reductive ring-opening of a D–A cyclopropane using D2 instead of H2 generated the corresponding monodeuterated product.
- Sone, Yoshitomo,Kimura, Yumi,Ota, Ryotaro,Mochizuki, Takehito,Ito, Junki,Nishii, Yoshinori
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supporting information
p. 2842 - 2847
(2017/05/29)
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- Cascade One-Pot Synthesis of Indanone-Fused Cyclopentanes from the Reaction of Donor-Acceptor Cyclopropanes and Enynals via a Sequential Hydrolysis/Knoevenagel Condensation/[3+2] Cycloaddition
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A cascade reaction of donor-acceptor cyclopropanes with enynals to construct indanone-fused cyclopentanes via a sequential hydrolysis/Knoevenagel condensation/[3+2] cycloaddition is reported. The desired indanone-fused cyclopentanes were obtained in good yields. This method features mild reaction conditions and broad substrate scope, which render it very appealing to chemists for the synthesis of complex molecules containing an indanone-fused cyclopentane moiety. Moreover, the products could be further converted into compounds with different functional groups through the well-known transformations. (Figure presented.).
- Zhang, Jiantao,Jiang, Huanfeng,Zhu, Shifa
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p. 2924 - 2930
(2017/09/08)
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- Scandium(III) Trifluoromethanesulfonate Catalyzed Selective Reactions of Donor–Acceptor Cyclopropanes with 1,1-Diphenylethanols: An Approach to Polysubstituted Olefins
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An unexpected synthetic approach to polysubstituted olefins through the scandium(III) trifluoromethanesulfonate catalyzed ring-opening reaction of donor–acceptor cyclopropanes with 1,1-diphenylethanols was developed. The reactions, which are experimentally easy to handle, feature tolerance of various functional groups and mild reaction conditions. On the basis of experimental evidence, a plausible mechanism was also proposed.
- Zhu, Xiaoyan,Hong, Gang,Hu, Chen,Wu, Shengying,Wang, Limin
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p. 1547 - 1551
(2017/04/01)
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- [3+2] Annulation of Donor-Acceptor Cyclopropanes with Vinyl Azides
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A Sc(OTf)3-catalyzed reaction of vinyl azides with donor-acceptor cyclopropanes affords highly functionalized azidocyclopentanes in a diastereoselective fashion. The resulting azidocyclopentanes could be transformed into various cyclic scaffolds.
- Kaga, Atsushi,Gandamana, Dhika Aditya,Tamura, Sayako,Demirelli, Mesut,Chiba, Shunsuke
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supporting information
p. 1091 - 1095
(2017/05/19)
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- Lewis Acid Catalyzed [3+3] Annulation of Donor–Acceptor Cyclopropanes with γ-Hydroxyenones: Access to Highly Functionalized Tetrahydropyrans
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Donor–acceptor cyclopropanes were engaged in a [3+3]-annulation reaction with γ-hydroxyenones. Sc(OTf)3was found to be the best catalyst, and 2,4,4,5-tetrasubstituted tetrahydropyran products were obtained in good yields under mild reaction con
- Mondal, Keshab,Pan, Subhas Chandra
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supporting information
p. 534 - 537
(2017/02/05)
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- Regioselective Hydrogenolysis of Donor-Acceptor Cyclopropanes with Zn-AcOH Reductive System
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A convenient low-cost method for regioselective ring-opening of donor-acceptor cyclopropanes with the Zn-AcOH reductive system was developed. The general character of the method was displayed via efficient reduction of a representative series of 2-(het)arylcyclopropane-1,1-diesters as well as donor-acceptor cyclopropanes with other types of electron-withdrawing activating groups. This method opens a rapid access to γ-substituted propyl-1,1-diesters, ketoesters, cyanoesters, cyanoamides, dinitriles, etc., many of which are not readily accessible with alternative methods. The utility of the synthesized compounds was demonstrated by transforming them into valuable acyclic and cyclic compounds (including pharmacologically relevant carbazoles, δ-lactams, and oxindole derivatives).
- Ivanov, Konstantin L.,Villemson, Elena V.,Latyshev, Gennadij V.,Bezzubov, Stanislav I.,Majouga, Alexander G.,Melnikov, Mikhail Ya.,Budynina, Ekaterina M.
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p. 9537 - 9549
(2017/09/23)
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- Sc(OTf)3-Catalyzed [3 + 3] Cycloaddition of Cyclopropane 1,1-Diesters with Phthalazinium Dicyanomethanides
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The Sc(OTf)3-catalyzed diastereoselective [3 + 3] cycloaddition of phthalazinium dicyanomethanides with cyclopropane 1,1-diesters proceeded smoothly under mild reaction conditions, affording a variety of 3,4-dihydro-1H-pyrido[2,1-a]phthalazine derivatives in up to 99% yields with excellent diastereoselectivities.
- Liu, Honglei,Yuan, Chunhao,Wu, Yang,Xiao, Yumei,Guo, Hongchao
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supporting information
p. 4220 - 4223
(2015/09/15)
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- A facile formal [2+1] cycloaddition of styrenes with alpha-bromocarbonyls catalyzed by copper: Efficient synthesis of donor-acceptor cyclopropanes
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Reactions of 2-bromoesters and styrenes underwent a [2+1] cycloaddition reaction, i.e., cyclopropanation, to produce donor-acceptor (D-A) cyclopropanes through a radical addition-ring closure process. In this reaction, the combination of copper(ii) comple
- Nishikata, Takashi,Noda, Yushi,Fujimoto, Ryo,Ishikawa, Shingo
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supporting information
p. 12843 - 12846
(2015/08/18)
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- Tetrahydro-1,3-oxazepines via Intramolecular Amination of Cyclopropylmethyl Cation
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An efficient synthesis of tetrahydro-1,3-oxazepines was developed involving the regioselective intramolecular amination of cyclopropylmethyl cation. The cation was generated by the abstraction of one imidate group in bis-imidate bearing a carbocation-stabilizing substituent. Using 1,1,2,3-tetrasubstituted cyclopropane substrates, highly diastereoselective intramolecular amination to trans-tetrahydro-1,3-oxazepines was achieved. The resulting tetrahydro-1,3-oxazepines were transformed to the homoallylamine derivatives in high yields.
- Skvorcova, Marija,Grigorjeva, Liene,Jirgensons, Aigars
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p. 2902 - 2904
(2015/06/30)
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- Catalysis and chemodivergence in the interrupted, formal homo-nazarov cyclization using allylsilanes
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A chemodivergent, Lewis acid catalyzed allylsilane interrupted formal homo-Nazarov cyclization is disclosed. With catalytic amounts of SnCl4 and in the presence of allyltrimethylsilane, a formal Hosomi-Sakurai-type allylation of the oxyallyl cation intermediate is observed. A variety of functionalized donor-acceptor cyclopropanes and allylsilanes were shown to be amenable to the reaction transformation and the allyl products were formed in up to 92% yield. Under dilute reaction conditions with stoichiometric SnCl4 and at reduced temperatures, an unusual formal [3 + 2]-cycloaddition between the allylsilane and the oxyallyl cation occurred to give hexahydrobenzofuran products in up to 69% yield.
- Shenje, Raynold,Williams, Corey W.,Francois, Katherine M.,France, Stefan
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supporting information
p. 6468 - 6471
(2015/02/05)
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- Cobalt porphyrin catalyzed [3+2] cycloaddition of cyclopropanes and carbonyl compounds
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A cobalt porphyrin efficiently catalyzed the formal [3+2] cycloaddition of alkyl-/aryl-substituted cyclopropanes and carbonyl compounds such as aldehydes and ketones to afford the corresponding substituted tetrahydrofurans. The use of the cobalt porphyrin complex as a Lewis acid to catalyze the reaction via the electrophilic activation of cyclopropanes was demonstrated. The high functional-group tolerance and robustness of the catalyst were also demonstrated. Further, the potential utility of the catalyst was demonstrated by performing the cycloaddition of cyclic ketones and cyclopropanes to afford spiro tetrahydrofurans. Georg Thieme Verlag Stuttgart · New York.
- Shiba, Takahiro,Kuroda, Daiki,Kurahashi, Takuya,Matsubara, Seijiro
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supporting information
p. 2005 - 2008
(2014/11/12)
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- A new type of donor-acceptor cyclopropane reactivity: The generation of formal 1,2- and 1,4-dipoles
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A new type of donor-acceptor cyclopropane reactivity has been discovered. On treatment with anhydrous GaCl3, they react as sources of even-numbered 1,2- and 1,4-dipoles instead of the classical odd-numbered 1,3-dipoles due to migration of positive charge from the benzyl center. This type of reactivity has been demonstrated for new reactions, namely, cyclodimerizations of donor-acceptor cyclopropanes that occur as [2+2]-, [3+2]-, [4+2]-, [5+2]-, [4+3]-, and [5+4]-annulations. The [4+2]-annulation of 2-arylcyclopropane-1,1-dicarboxylates to give polysubstituted 2-aryltetralins has been developed in a preparative version that provides exceedingly high regio- and diastereoselectivity and high yields. The strategy for selective hetero-combination of donor-acceptor cyclopropanes was also been developed. The mechanisms of the discovered reactions involving the formation of a comparatively stable 1,2-ylide intermediate have been studied. Old ring, new reactivity: A new type of donor-acceptor cyclopropane reactivity has been discovered. On treatment with anhydrous GaCl3, they react as sources of even-numbered 1,2- and 1,4-dipoles instead of the classical odd-numbered 1,3-dipoles owing to the migration of positive charge from the benzyl center.
- Novikov, Roman A.,Tarasova, Anna V.,Korolev, Victor A.,Timofeev, Vladimir P.,Tomilov, Yury V.
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p. 3187 - 3191
(2014/04/03)
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- TiCl4 promoted formal [3 + 3] cycloaddition of cyclopropane 1,1-diesters with azides: Synthesis of highly functionalized triazinines and azetidines
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A TiCl4 promoted formal [3 + 3] cycloaddition of cyclopropane 1,1-diesters with azides has been developed for the synthesis of highly functionalized triazinines. Both stoichiometric and substoichiometric versions of this reaction were accomplished dependent on the choice of solvent. It is noteworthy that the corresponding products could be easily converted to biologically important azetidines by simple thermolysis.
- Zhang, Huan-Huan,Luo, Yong-Chun,Wang, Hua-Peng,Chen, Wei,Xu, Peng-Fei
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p. 4896 - 4899
(2015/04/27)
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- A route to highly functionalized-enaminoesters via a domino ring-opening cyclization/decarboxylative tautomerization sequence of donor-acceptor cyclopropanes with substituted malononitriles
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An unprecedented and domino synthetic strategy for the synthesis of highly functionalized carbocyclic-enaminoesters bearing an all-carbon quaternary center via Yb(OTf)3-catalyzed ring-opening cyclization/decarboxylative tautomerization of donor-acceptor cyclopropanes with 2-alkyl malononitriles in excellent yields is described. The products are obtained as a single diastereomer in most cases where the nitrile and aryl groups are aligning in a cis orientation across the ring.
- Ghorai, Manas K.,Talukdar, Ranadeep,Tiwari, Deo Prakash
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supporting information
p. 2204 - 2207
(2014/05/06)
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- Diastereoselective synthesis of functionalized tetrahydrocarbazoles via a domino-ring opening-cyclization of donor-acceptor cyclopropanes with substituted 2-vinylindoles
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A new domino synthetic approach for the synthesis of highly functionalized tetrahydrocarbazoles via DROC of various functionalized DA-cyclopropanes with 2-indolylnitroethylene and indole-substituted alkylidene malonate is described. The tetrahydrocarbazol
- Talukdar, Ranadeep,Tiwari, Deo Prakash,Saha, Amrita,Ghorai, Manas K.
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supporting information
p. 3954 - 3957
(2014/08/18)
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- Stereoselective double lewis acid/organo-catalyzed dimerization of donor-acceptor cyclopropanes into substituted 2-oxabicyclo[3.3.0]octanes
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A new approach for the dimerization of donor-acceptor cyclopropanes (2-arylcyclopropane-1,1-dicarboxylates) under double-catalysis conditions by treatment with 20 mol % of GaCl3 and dimethyl 3,5-dimethyl-1- pyrazoline-3,5-dicarboxylate as a specific organocatalyst has been found. Under these conditions, the starting compounds are regio- and stereospecifically converted into polysubstituted 2-oxabicyclo[3.3.0]octanes. Two new rings, one C-O bond, and two C-C bonds are formed in this process, and four stereocenters are thus created. The reaction mechanism was thoroughly studied by NMR spectroscopy, and a number of intermediates were detected.
- Novikov, Roman A.,Timofeev, Vladimir P.,Tomilov, Yury V.
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p. 5993 - 6006
(2012/10/08)
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- Lewis acid mediated (3 + 2) cycloadditions of donor-acceptor cyclopropanes with heterocumulenes
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Isocyanates, isothiocyanates, and carbodiimides are effective substrates in (3 + 2) cycloadditions with donor-acceptor cyclopropanes for the synthesis of five-membered heterocycles. These reactions exhibit a broad substrate scope, high yields, and well-defined chemoselectivity. Discussed herein are the implications of Lewis acid choice on the stereochemical outcome and the reaction mechanism.
- Goldberg, Alexander F. G.,O'Connor, Nicholas R.,Craig, Robert A.,Stoltz, Brian M.
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p. 5314 - 5317,4
(2012/12/12)
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- Lewis acid mediated (3 + 2) cycloadditions of donor-acceptor cyclopropanes with heterocumulenes
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Isocyanates, isothiocyanates, and carbodiimides are effective substrates in (3 + 2) cycloadditions with donor-acceptor cyclopropanes for the synthesis of five-membered heterocycles. These reactions exhibit a broad substrate scope, high yields, and well-defined chemoselectivity. Discussed herein are the implications of Lewis acid choice on the stereochemical outcome and the reaction mechanism.
- Goldberg, Alexander F. G.,O'Connor, Nicholas R.,Craig, Robert A.,Stoltz, Brian M.
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p. 5314 - 5317
(2013/01/15)
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- Design, preparation, X-ray crystal structure, and reactivity of o-alkoxyphenyliodonium bis(methoxycarbonyl)methanide, a highly soluble carbene precursor
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The preparation, X-ray structure, and reactivity of new, highly soluble, and reactive iodonium ylides derived from malonate methyl ester and bearing an ortho substituent on the phenyl ring are reported. These new reagents show higher reactivity than common phenyliodonium ylides in the Rh-catalyzed cyclopropanation, C-H insertion, and transylidation reactions under homogeneous conditions.
- Zhu, Chenjie,Yoshimura, Akira,Ji, Lei,Wei, Yunyang,Nemykin, Victor N.,Zhdankin, Viktor V.
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supporting information; scheme or table
p. 3170 - 3173
(2012/08/07)
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- Formal homo-nazarov and other cyclization reactions of activated cyclopropanes
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The Nazarov cyclization of divinyl ketones gives access to cyclopentenones. Replacing one of the vinyl groups by a cyclopropane leads to a formal homo-Nazarov process for the synthesis of cyclohexenones. In contrast to the Nazarov reaction, the cyclization of vinyl-cyclopropyl ketones is a stepwise process, often requiring harsh conditions. Herein, we describe two different approaches for further polarization of the three-membered ring of vinyl-cyclopropyl ketones to allow the formal homo-Nazarov reaction under mild catalytic conditions. In the first approach, the introduction of an ester group α to the carbonyl on the cyclopropane gave a more than tenfold increase in reaction rate, allowing us to extend the scope of the reaction to non-electron-rich aryl donor substituents in the β position to the carbonyl on the cyclopropane. In this case, a proof of principle for asymmetric induction could be achieved using chiral Lewis acid catalysts. In the second approach, heteroatoms, especially nitrogen, were introduced β to the carbonyl on the cyclopropane. In this case, the reaction was especially successful when the vinyl group was replaced by an indole heterocycle. With a free indole, the formal homo-Nazarov cyclization on the C3 position of indole was observed using a copper catalyst. In contrast, a new cyclization reaction on the N1 position was observed with BrAnsted acid catalysts. Both reactions were applied to the synthesis of natural alkaloids. Preliminary investigations on the rationalization of the observed regioselectivity are also reported.
- De Simone, Filippo,Saget, Tanguy,Benfatti, Fides,Almeida, Sofia,Waser, Jerome
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supporting information; experimental part
p. 14527 - 14538
(2012/02/04)
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- Thermally induced cycloadditions of donor/acceptor carbenes
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The thermal decomposition of aryldiazoacetates and aryldiazoketones in the absence of a catalyst leads to synthetically useful transformations. The thermal reaction of aryldiazoacetates with alkenes generates cyclopropanes in 68-97% yield and with good diastereoselectivity (up to 19:1 dr) when the aryl substituent is electron-rich. The thermal reaction of aryldiazoketones with alkenes generated cyclobutanones in 71-94% yield and with good diastereocontrol (≥9:1 dr).
- Ovalles, Stephanie R.,Hansen, Jorn H.,Davies, Huw M. L.
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supporting information; experimental part
p. 4284 - 4287
(2011/10/08)
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- Synthesis of functionalized dihydrothiophenes from doubly activated cyclopropanes using tetrathiomolybdate as the sulfur transfer reagent
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A number of doubly activated cyclopropanes were synthesized starting from various substituted bromosulfonium bromides in good yield. Regioselective ring-opening of cyclopropanes with tetrathiomolybdate as the sulfur transfer reagent gave dihydrothiophenes
- Gopinath, Purushothaman,Chandrasekaran, Srinivasan
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experimental part
p. 700 - 703
(2011/03/20)
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- Cyclodimerization of 2-arylcyclopropane-1,1-diesters. Lewis acid induced reversion of cyclopropane umpolung
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A novel Lewis acid catalyzed [3+2] cyclodimerization of 2-arylcyclopropane-1,1-dicarboxylates is reported. It is the first example of a reaction wherein a donor-acceptor cyclopropane provides two carbons in a newly formed ring. The described cyclodimeriza
- Chagarovskiy, Alexey O.,Ivanova, Olga A.,Budynina, Ekaterina M.,Trushkov, Igor V.,Melnikov, Mikhail Ya.
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supporting information; experimental part
p. 4421 - 4425
(2011/09/19)
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- Lewis acid-catalyzed isomerization of 2-arylcyclopropane-1,1- dicarboxylates: A new efficient route to 2-styrylmalonates
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A facile efficient approach to the 2-styrylmalonates via the Lewis acid-catalyzed isomerization of 2-arylcyclopropane-1,1-dicarboxylates has been developed. The efficiency of this method was demonstrated for a representative series of such cyclopropanes.
- Chagarovskiy, Alexey O.,Ivanova, Olga A.,Rakhmankulov, Eduard R.,Budynina, Ekaterina M.,Trushkov, Igor V.,Melnikov, Mikhail Ya.
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supporting information; experimental part
p. 3179 - 3184
(2011/02/22)
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- General method for the synthesis of phenyliodonium ylides from malonate esters: Easy access to 1,1-cyclopropane diesters
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(Chemical Equation Presented) A general method to access phenyliodonium ylides from malonates has been developed. These ylides provide easy access to a variety of useful 1,1-cyclopropane diesters using rhodium or copper catalysis. Moreover, the iodonium ylide of dimethyl malonate was obtained in 78% yield using improved conditions that involve a simple filtration step to isolate the desired product. This ylide was shown to be a safer and convenient alternative to the corresponding diazo compound and a very efficient way to 1,1-cyclopropane diesters when used with a catalytic amount of Rh2(esp)2.
- Goudreau, Sébastien R.,Marcoux, David,Charette, André B.
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supporting information; experimental part
p. 470 - 473
(2009/04/10)
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- trans-directing ability of the amide group: Enabling the enantiocontrol in the synthesis of 1,1-dicarboxy cyclopropanes. Reaction development, scope, and synthetic applications
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(Chemical Equation Presented) In this article, we describe our efforts toward the enantioselective formation of 1,1-cyclopropane diesters via the metal-catalyzed cyclopropanation of olefins. The strategies envisioned to achieve such a goal are discussed a
- Marcoux, David,Goudreau, Sebastien R.,Charette, Andre B.
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scheme or table
p. 8939 - 8955
(2010/03/02)
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- Synthesis of cyclohexanes via [3 + 3] hexannulation of cyclopropanes and 2-chloromethyl allylsilanes
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Lewis acid-assisted ring-opening/allylation of 1,1-cyclopropane diesters, followed by base-mediated ring closure, generates functionalized exo-methylenecyclohexanes in good yield. This two-step procedure is highlighted by expedient preparation of a pyrido
- Sapeta, Katarina,Kerr, Michael A.
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supporting information; experimental part
p. 2081 - 2084
(2009/09/30)
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- Cycloadditions of aromatic azomethine imines with 1,1-cyclopropane Diesters
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The cycloaddition of aromatic azomethine imines to 1,1-cyclopropane diesters was achieved using Ni(CIO4)2 as catalyst. The methodology gives access to unique tricyclic dihydroquinoline derivatives with dr up to 6.6:1. A nonconcerted
- Perreault, Christian,Goudreau, Sbastien R.,Zimmer, Lucie E.,Charette, Andr B.
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supporting information; experimental part
p. 689 - 692
(2009/04/06)
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- Rhodium-catalyzed cyclopropanation of alkenes with dimethyl diazomalonate
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The outstanding ability of dirhodium α,α,α′, α′-tetramethyl-1,3-benzenedipropanoate [Rh2(esp) 2; esp=α,α,α′,α′-tetramethyl-1,3- benzene-dipropanoate] to catalyze the cyclopropanation of a wide range of alkenes with malonate-derived carbenoids under mild reaction conditions is reported in this communication. The experimental protocol is remarkably simple, uses readily accessible and stable dimethyl diazomalonate with very low catalyst loading. More importantly, the alkene is employed as a limiting reagent.
- Gonzalez-Bobes, Francisco,Fenster, Michael D. B.,Kiau, Susanne,Kolla, Laxma,Kolotuchin, Sergei,Soumeillant, Maxime
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supporting information; experimental part
p. 813 - 816
(2009/04/21)
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- Scope and mechanism for Lewis acid-catalyzed cycloadditions of aldehydes and donor-acceptor cyclopropanes: Evidence for a stereospecific intimate ion pair pathway
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In this work, the one-step diastereoselective synthesis of cis-2,5-disubstituted tetrahydrofurans via Lewis acid catalyzed [3 + 2] cycloadditions of donor-acceptor (D-A) cyclopropanes and aldehydes is described. The scope and limitations with respect to both reaction partners are provided. A detailed examination of the mechanism has been performed, including stereochemical analysis and electronic profiling of both reactants. Experimental evidence supports an unusual stereospecific intimate ion pair mechanism wherein the aldehyde functions as a nucleophile and malonate acts as the nucleofuge. The reaction proceeds with inversion at the cyclopropane donor site and allows absolute stereochemical information to be transferred to the products with high fidelity. The mechanism facilitates the stereospecific synthesis of a range of optically active tetrahydrofuran derivatives from enantioenriched D-A cyclopropanes.
- Pohlhaus, Patrick D.,Sanders, Shanina D.,Parsons, Andrew T.,Li, Wei,Johnson, Jeffrey S.
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p. 8642 - 8650
(2008/12/23)
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- Diazo compounds and phenyliodonium ylides in inter- and intramolecular cyclopropanations catalyzed by dirhodium(II). Synthesis and chiral resolution by GC versus HPLC
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The dirhodium(II)-catalyzed intermolecular cyclopropanation of a set of olefins with either diazo free phenyliodonium ylides or diazo compounds afforded cyclopropanes derived from Meldrum's acid, dimethyl malonate, (silanoxyvinyl)diazoacetates, 3,3,3-trifluoro-2-diazopropionate, ethyl diazo(triethyl)- and (dimethylphenyl)silylacetate with moderate to high yield in either racemic or enantio-enriched forms. The intramolecular cyclopropanation of triethylsilyl-substituted allyl diazo-acetates in the presence of the chiral rhodium(II) catalyst [Rh2(s-nttl)4] in toluene afforded the corresponding cyclopropanes with up to 37% ee. An efficient chiral separation method based on enantioselective GC and HPLC was developed. The method provides information about the chemical yields of the cyclopropane products, enantioselectivity, substrate specifity, and catalytic activity of the chiral catalysts used in the inter- and intramolecular cyclopropanation reactions and avoids time-consuming work-up procedures. Springer-Verlag 2005.
- Ghanem, Ashraf,Lacrampe, Fabienne,Aboul-Enein, Hassan Y.,Schurig, Volker
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p. 1205 - 1219
(2007/10/03)
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- Rhodium(II)-catalyzed inter- and intramolecular cyclopropanations with diazo compounds and phenyliodonium ylides: Synthesis and chiral analysis
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Different classes of cyclopropanes derived from Meldrum's acid (=2,2-dimethyl-1,3-dioxane-4,6-dione; 4), dimethyl malonate (5), 2-diazo-3-(silyloxy)but-3-enoate 16, 2-diazo-3,3,3-trifluoropropanoate 18, diazo(triethylsilyl)acetate 24a, and diazo(dimethylphenylsilyl)acetate 24b were prepared via dirhodium(II)-catalyzed intermolecular cyclopropanation of a set of olefins 3 (Schemes 1 and 4-6). The reactions proceeded with either diazo-free phenyliodonium ylides or diazo compounds affording the desired cyclopropane derivatives in either racemic or enantiomer-enriched forms. The intramolecular cyclopropanation, of allyl diazo(triethylsilyl)acetates 28, 30, and 33 were carried out in the presence of the chiral dirhodium(II) catalyst [Rh 2{(S)-nttl)4}] (9) in toluene to afford the corresponding cyclopropane derivatives 29, 31 and 34 with up to 37% ee (Scheme 7). An efficient enantioselective chiral separation method based on enantioselective GC and HPLC was developed. The method provides information about the chemical yields of the cyclopropane derivatives, enantioselectivity, substrate specifity, and catalytic activity of the chiral catalysts used in the inter- and intramolecular cyclopropanation reactions and avoids time-consuming workup procedures.
- Ghanem, Ashraf,Lacrampe, Fabienne,Schurig, Volker
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p. 216 - 239
(2007/10/03)
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- RhII-catalyzed thermal cyclopropanations of a phenyliodonium bis(carbomethoxy)methylide with alkenes and dienes
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Iodonium ylide 2, derived front dimethyl malonate, undergoes facile thermal cycloaddition with alkenes and dienes catalyzed with Rh2(OAc)4 to form the corresponding cyclopropanedicarboxylates and vinylcyclopropanedicarboxylates, resp
- Georgakopoulou,Kalogiros,Hadjiarapoglou
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p. 1843 - 1846
(2007/10/03)
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- Effect of diazoalkane structure on the stereoselectivity of rhodium(II) (S)-N-(arylsulfonyl)prolinate catalyzed cyclopropanations
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Rhodium(II) (S)-N-(arylsulfonyl)prolinate catalyzed decomposition of diazoalkanes containing a methyl ester and either a vinyl or a phenyl group in the presence of alkenes results in highly diastereoselective and enantioselective cyclopropanations.
- Davies, Huw M. L.,Bruzinski, Paul R.,Fall, Michael J.
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p. 4133 - 4136
(2007/10/03)
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- 77. Carbenoid Reactions in Rhodium(II)-Catalyzed Decomposition of Iodonium Ylides
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The intermediacy of metallocarbenes in decomposition reactions of iodonium ylides with was established by comparison with reactions of the corresponding diazo compounds.The sensitivity of the RhII-catalyzed intermolecular cyclopropa
- Mueller, Paul,Fernandez, Daniel
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p. 947 - 958
(2007/10/02)
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