17608-67-2Relevant academic research and scientific papers
Rhodium Porphyrin Catalyzed Regioselective Transfer Hydrogenolysis of C-C σ-Bonds in Cyclopropanes with iPrOH
Chen, Chen,Feng, Shiyu,Chan, Kin Shing
, p. 2582 - 2589 (2019)
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.
Diastereoselective reactions and rearrangements of chiral allylic sulfoximines
Pyne, Stephen G.,Dong,David,O'Meara
, p. 275 - 289 (1997)
The nucleophilic and electrophilic chemistry of chiral allylic sulfominines and their alkyl sulfoximine counterparts are described including the synthesis of highly functionalised cyclopropanes derivatives. The synthesis of primary and secondary N-tosyl a
Organoselenium-Catalyzed Asymmetric Cyclopropanations of (E)-Chalcones
Chein, Rong-Jie,Cheng, Pei-Tung,Tseng, Yu-Hsun
supporting information, p. 8104 - 8108 (2021/10/25)
We report a new class of chiral tetrahydroselenophene based on (S)-diphenyl(tetrahydroselenophen-2-yl)methanol, which was prepared from (R)-3-(3-bromopropyl)-2,2-diphenyloxirane and sodium selenide. These chiral tetrahydroselenophene-based compounds were used to catalyze asymmetric cyclopropanation reactions; the selenonium ylide intermediates formed from these selenium-containing catalysts and benzyl bromide efficiently react with (E)-chalcones to give various cyclopropanes (27 examples) with excellent enantioselectivities of ≤99% ee and are the first examples of organoselenium-catalyzed asymmetric cyclopropanations.
Enhanced diastereoselectivity via confinement: Diastereoselective photoisomerization of 2,3-diphenyl-1-benzoylcyclopropane derivatives within zeolites
Sivaguru,Sunoj, Raghavan B.,Wada, Takehiko,Origane, Yumi,Inoue, Yoshihisa,Ramamurthy
, p. 5528 - 5536 (2007/10/03)
Photochemistry of optically pure trans-2,3-diphenyl-1-benzoylcyclopropane has been examined in isotropic solution and within zeolites. Results suggest that it isomerizes by cleavage of either the C1-C2 or C1-C3
Catalytic cyclopropanation of electron deficient alkenes mediated by chiral and achiral sulfides: Scope and limitations in reactions involving phenyldiazomethane and ethyl diazoacetate
Aggarwal, Varinder K.,Smitha, Helen W.,Hynd, George,Jones, Ray V.H.,Fieldhouse, Robin,Spey, Sharon E.
, p. 3267 - 3276 (2007/10/03)
Phenyldiazomethane reacts with electron deficient alkenes in the presence of catalytic amounts of transition metal catalyst [Rh2(OAc)4 was better than Cu(acac)2] and catalytic amounts of sulfide to give cyclopropanes. Pentamethylene sulfide was found to be superior to tetrahydrothiophene and the optimum solvent was toluene. Under these optimised conditions a range of enones were cyclopropanated in high yields. Cyclic enones and acrylates were not successful in this process. The use of the chiral 1,3-oxathiane derived from camphorsulfonyl chloride in 2 steps in this process furnished cyclopropanes in good yield and very high enantiomeric excess (>97% ee). The absolute stereochemistry of cyclopropane 10 was proven by X-ray analysis and the origin of the stereochemical induction has been rationalised. Extension of this work to include diazoesters was partially successful. Again pentamethylene sulfide was found to be superior to tetrahydrothiophene, but this time both Rh2(OAc)4 and Cu(acac)2 were found to be equally effective. Enones, fumarates and unsaturated nitro compounds worked well but simple acrylates and unsaturated aldehydes were not effective substrates. Control experiments were conducted in which the stabilised ylide was isolated and reacted with the less successful substrates and, whilst unsaturated aldehydes still gave low yields, simple acrylates gave high yields of the corresponding cyclopropane. The use of the chiral 1,3-oxathiane was not successful with these more stable diazo compounds.
Generation of Diastereomeric Cyclopropanes from Benzylidenesulfuranes and Chalcones
Stahl, Ingfried,Schomburg, Sabine,Kalinowski, Hans Otto
, p. 2247 - 2260 (2007/10/02)
The reaction of the benzylidenesulfuranes 2, available by deprotonation of the benzylsulfonium bromides 1, with chalcones 3, which are substituted in the aroyl part, leads to the stereoisomeric cyclopropanes 4 and 5.The stereochemistry of 4 and 5 is elucidated by spectroscopy.A carbenic mechanism of formation of 4 and 5 is excluded experimentally.
