4606-10-4Relevant articles and documents
Computational chemical analysis of Ru(II)-Pheox–catalyzed highly enantioselective intramolecular cyclopropanation reactions
Nakagawa, Yoko,Nakayama, Naofumi,Goto, Hitoshi,Fujisawa, Ikuhide,Chanthamath, Soda,Shibatomi, Kazutaka,Iwasa, Seiji
, p. 52 - 61 (2018/12/11)
Computational chemical analysis of Ru(II)-Pheox–catalyzed highly enantioselective intramolecular cyclopropanation reactions was performed using density functional theory (DFT). In this study, cyclopropane ring–fused γ-lactones, which are 5.8?kcal/mol more stable than the corresponding minor enantiomer, are obtained as the major product. The results of the calculations suggest that the enantioselectivity of the Ru(II)-Pheox–catalyzed intramolecular cyclopropanation reaction is affected by the energy differences between the starting structures 5l and 5i. The reaction pathway was found to be a stepwise mechanism that proceeds through the formation of a metallacyclobutane intermediate. This is the first example of a computational chemical analysis of enantioselective control in an intramolecular carbene-transfer reaction using C1-symmetric catalysts.
In situ generation of nitrile oxides from copper carbene and tert -butyl nitrite: Synthesis of fully substituted isoxazoles
Chen, Rongxiang,Ogunlana, Abosede Adejoke,Fang, Shangwen,Long, Wenhao,Sun, Hongmei,Bao, Xiaoguang,Wan, Xiaobing
supporting information, p. 4683 - 4687 (2018/07/06)
Herein, we present a novel [3 + 2] cycloaddition reaction of β-keto esters with nitrile oxides, which were generated in situ from copper carbene and tert-butyl nitrite. This three-component reaction provides new methodology for the direct synthesis of fully substituted isoxazole derivatives, featuring mild reaction conditions, readily accessible starting materials and simple operation. The experimental studies and DFT calculations suggest that the reaction starts with the generation of the key intermediate nitrile oxides, followed by a [3 + 2] cycloaddition reaction of β-keto esters to give the final isoxazole products.
Intramolecular cyclopropanation of bromodiazoacetates
Bolsones, Marianne,Bonge-Hansen, Hanne Therese,Bonge-Hansen, Tore
supporting information, p. 221 - 224 (2014/02/14)
A series of allylic diazoacetates were prepared from the corresponding allylic alcohols and bromoacetyl bromide. When the allylic diazoacetates were treated with 1,8-diazabicyclo[5.4.0]undec-7-ene and N-bromosuccinimide, a rapid full conversion to the corresponding allylic bromodiazoacetates occurred. Exposure of the allylic bromodiazoacetates to rhodium(II) catalysts induced an intramolecular cyclopropanation and gave cyclopropyl bromolactones in yields that were low to good, depending on the substitution pattern. Georg Thieme Verlag Stuttgart New York.
Synthesis and biological evaluation of novel 2-(1H-imidazol-4-yl)cyclopropane carboxylic acids: key intermediates for H3 histamine receptor ligands.
Brana, Miguel F,Guisado, Cristina,Fernando Alguacil, Luis,Garrido, Elisa,Perez-Garcia, Carmen,Ruiz-Gayo, Mariano
, p. 3561 - 3563 (2007/10/03)
A new synthetic methodology to provide cis-2-(1H-imidazol-4-yl)-cyclopropane carboxylic acids is described. These cyclopropanes are useful for the preparation of novel H(3) receptor agents.
