879324-63-7Relevant academic research and scientific papers
A transition-metal-free & diazo-free styrene cyclopropanation
Herraiz, Ana G.,Suero, Marcos G.
, p. 9374 - 9379 (2019/10/22)
An operationally simple and broadly applicable novel cyclopropanation of styrenes using gem-diiodomethyl carbonyl reagents has been developed. Visible-light triggered the photoinduced generation of iodomethyl carbonyl radicals, able to cyclopropanate a wide array of styrenes with excellent chemoselectivity and functional group tolerance. To highlight the utility of our photocyclopropanation, we demonstrated the late-stage functionalization of biomolecule derivatives.
High-valent tin(IV) porphyrins: Efficient and selective catalysts for cyclopropanation of styrene derivatives with EDA under mild conditions
Gharaati, Shadab,Moghadamb, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Barati, Behjat,Sadegh, Faranaz
, p. 78 - 82 (2013/10/01)
An efficient and selective method for cyclopropanation of styrene derivatives with ethyl diazoacetate (EDA) catalyzed by tin(IV) tetraphenylporphyrinato trifluoromethanesulfonate, [SnIV(TPP)(OTf)2], and tin(IV)tetraphenylporphyrinato tetrafluoroborate, [SnIV(TPP)(BF 4)2] is reported. These electron-deficient catalysts catalyzed the cyclopropanation of styrene derivatives in high yields and short reaction times under mild conditions. The reactions were highly selective and only trans-isomers were produced. Electron-rich styrenes were reacted faster than electron-poor ones. The catalysts were reused several times without loss of their catalytic activity and diastereoselectivity.
A general mechanism for the copper- and silver-catalyzed olefin aziridination reactions: Concomitant involvement of the singlet and triplet pathways
Maestre, Lourdes,Sameera,Díaz-Requejo, M. Mar,Maseras, Feliu,Pérez, Pedro J.
supporting information, p. 1338 - 1348 (2013/03/28)
The olefin aziridination reactions catalyzed by copper and silver complexes bearing hydrotris(pyrazolyl)borate (Tpx) ligands have been investigated from a mechanistic point of view. Several mechanistic probe reactions were carried out, specifically competition experiments with p-substituted styrenes, stereospecificity of olefins, effects of the radical inhibitors, and use of a radical clock. Data from these experiments seem to be contradictory, as they do not fully support the previously reported concerted or stepwise mechanisms. But theoretical calculations have provided the reaction profiles for both the silver and copper systems with different olefins to satisfy all experimental data. A mechanistic proposal has been made on the basis of the information that we collected from experimental and theoretical studies. In all cases, the reaction starts with the formation of a metal-nitrene species that holds some radical character, and therefore the aziridination reaction proceeds through the radical mechanism. The silver-based systems however hold a minimum energy crossing point (MECP) between the triplet and closed-shell singlet surfaces, which induce the direct formation of the aziridines, and stereochemistry of the olefin is retained. In the case of copper, a radical intermediate is formed, and this intermediate constitutes the starting point for competition steps involving ring-closure (through a MECP between the open-shell singlet and triplet surfaces) or carbon-carbon bond rotation, and explains the loss of stereochemistry with a given substrate. Overall, all the initially contradictory experimental data fit in a mechanistic proposal that involves both the singlet and the triplet pathways.
A RuII-N-heterocyclic carbene (NHC) complex from metal-metal singly bonded diruthenium(I) precursor: Synthesis, structure and catalytic evaluation
Sinha, Arup,Daw, Prosenjit,Rahaman, S.M. Wahidur,Saha, Biswajit,Bera, Jitendra K.
experimental part, p. 1248 - 1257 (2011/04/22)
A mononuclear Ru(II)-N-heterocyclic carbene (NHC) complex [Ru II(CO)2(κ2C,N-BIN)(H2O)Br] [OTf] (OTf = trifluoromethane sulphonate) (1) has been synthesized in high-yield by the oxidative cleavage of the metal-metal singly-bonded diruthenium(I) precursor [Ru2(CO)4(CH3CN)6(OTf) 2] with 1,8-naphthyridine functionalized NHC precursor 1-benzyl-3-(5,7-dimethyl-1,8-naphthyrid-2-yl)imidazolium bromide (BIN·HBr) at room temperature. Compound 1 catalyzes transfer hydrogenation of ketones to alcohols, and carbene-transfer from ethyl diazoacetate to a variety of substrates. It is shown to be an excellent catalyst for the insertion of carbene into the O-H and N-H bonds of alcohols and amines.
Soluble Polymer-Supported Ruthenium Porphyrin Catalysts for Epoxidation, Cyclopropanation, and Aziridination of Alkenes
Zhang, Jun-Long,Che, Chi-Ming
, p. 1911 - 1914 (2007/10/03)
(Matrix Presented) Attachment of poly(ethylene glycol) (PEG) to ruthenium porphyrin via a covalent etheric bond gives soluble polymer-supported ruthenium catalysts 3-5. These catalysts exhibit high reactivity and selectivity toward alkene epoxidation with 2,6-dichloropyridine N-oxide and alkene cyclopropanation with diazo compounds. The application of these catalysts in the synthesis of unstable organic compounds has been demonstrated.
Cyclopropanation reactions catalysed by rhodium(I) complexes with new anionic carborane phosphine ligands
Demonceau,Simal,Noels,Vinas,Nunez,Teixidor
, p. 7879 - 7882 (2007/10/03)
The first set of rhodium(I) complexes 1-3 has been shown to be active for the cyclopropanation of olefins with diazoaeetates.
