3709-20-4Relevant academic research and scientific papers
Ni-Catalyzed [8+3] cycloaddition of tropones with 1,1-cyclopropanediesters
Tejero, Ruben,Ponce, Alberto,Adrio, Javier,Carretero, Juan C.
, p. 10406 - 10408 (2013)
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.
Stable dicarbonylcarbene complexes of bis(oxazolinyl)pyridine ruthenium and osmium
Nishiyama, Hisao,Aoki, Katsuyuki,Itoh, Hirofumi,Iwamura, Taichiro,Sakata, Naoya,Kurihara, Osamu,Motoyama, Yukihiro
, p. 1071 - 1072 (1996)
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.
(3+2)-Cycloaddition of Donor-Acceptor Cyclopropanes with Thiocyanate: A Facile and Efficient Synthesis of 2-Amino-4,5-dihydrothiophenes
Jacob, Anu,Barkawitz, Philip,Andreev, Ivan A.,Ratmanova, Nina K.,Trushkov, Igor V.,Werz, Daniel B.
supporting information, p. 901 - 904 (2021/03/17)
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.
Synthesis of Substituted β-Styrylmalonates by Sequential Isomerization of 2-Arylcyclopropane-1,1-dicarboxylates and (2-Arylethylidene)malonates
Borisov, Denis D.,Chermashentsev, Grigorii R.,Novikov, Roman A.,Tomilov, Yury V.
supporting information, p. 2253 - 2259 (2021/03/04)
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.
Electricity Driven 1,3-Oxohydroxylation of Donor-Acceptor Cyclopropanes: a Mild and Straightforward Access to β-Hydroxy Ketones
Banerjee, Prabal,Maajid Taily, Irshad,Saha, Debarshi
, p. 5053 - 5057 (2021/09/30)
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.
(3 + 2)-Cycloaddition of Donor-Acceptor Cyclopropanes with Selenocyanate: Synthesis of Dihydroselenophenes and Selenophenes
Jacob, Anu,Jones, Peter G.,Werz, Daniel B.
supporting information, (2020/11/13)
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.
Blue LED Irradiation of Iodonium Ylides Gives Diradical Intermediates for Efficient Metal-free Cyclopropanation with Alkenes
Chidley, Tristan,Jameel, Islam,Rizwan, Shafa,Peixoto, Philippe A.,Pouységu, Laurent,Quideau, Stéphane,Hopkins, W. Scott,Murphy, Graham K.
, p. 16959 - 16965 (2019/11/11)
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
Stereospecific copper(II)-catalyzed tandem ring opening/oxidative alkylation of donor-acceptor cyclopropanes with hydrazones: Synthesis of tetrahydropyridazines
Mishra, Manmath,De, Pinaki Bhusan,Pradhan, Sourav,Punniyamurthy, Tharmalingam
, p. 10901 - 10910 (2019/09/13)
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.
Formal Insertion of Thioketenes into Donor-Acceptor Cyclopropanes by Lewis Acid Catalysis
Augustin, André U.,Busse, Marius,Jones, Peter G.,Werz, Daniel B.
supporting information, p. 820 - 823 (2018/02/10)
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.
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
Wang, Zhe-Hao,Zhang, Huan-Huan,Xu, Peng-Fei,Luo, Yong-Chun
, p. 10128 - 10131 (2018/09/13)
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
