16606-55-6Relevant articles and documents
Mechanism and origins of enantioselectivity for [BMIM]Cl ionic liquids and ZnCl2 co-catalyzed coupling reaction of CO2 with epoxides
Wang, Fang,Xu, Chuanzhi,Li, Zhen,Xia, Chungu,Chen, Jing
, p. 133 - 140 (2014)
Aiming at gaining more insight into the high catalytic activity of ZnCl2/[BMIM]Cl co-catalysts and elucidating the origination about the product enantioselectivity for the coupling reaction of CO2 with epoxides, a mechanistic study has been conducted by performing density functional theory calculations. The calculated results indicate a new stable complex [BMIM]ZnCl3 is probably formed via the dissociation of the in situ generated [BMIM]2ZnCl4 complex in the reaction system. This complex combined with another Cl- jointly assists the break of CO bond of propylene oxide (PO), which is the rate-determining step for the coupling reaction, and the corresponding barrier (28.0 kcal mol -1) is effectively lowered in comparison with the reaction promoted only by ZnCl2 (65.9 kcal mol-1) or [BMIM]Cl (33.1 kcal mol-1). [BMIM]+ takes part in the reaction by directly or indirectly stabilizing the intermediates and transition states via hydrogen bonding interaction with O of PO or Cl- in the reaction system. The observed product enantioselectivity probably originates from the formation of an interesting intermediate which provides nearly equal opportunities for inserted CO2 to attack the chiral carbon atom of PO on both sides and hence facilitates the formation of both R-product and S-product.
Efficient catalytic synthesis of optically active cyclic carbonates via coupling reaction of epoxides and carbon dioxide
Chen, Shu-Wei,Kawthekar, Rahul B.,Kim, Geon-Joong
, p. 297 - 300 (2007)
Chiral Co(salen) complexes bearing the Lewis acid of group 13 can efficiently catalyze the reactions of carbon dioxide with epoxides in the presence of catalytic amounts of alkali metal salts, quaternary ammonium halide or ionic liquids. They exhibited ex
Enantioselective synthesis of (R)-propylene carbonate from ethyl (S)-lactate
Whitaker, John M.,Ronald, Robert C.
, p. 1403 - 1404 (2009)
We report a three-step synthesis of (R)-propylene carbonate from inexpensive, chiral ethyl (S)-lactate. The synthesis involves a borohydride ester reduction and an unusual intramolecular displacement reaction by a carbonate anion. The procedure is simple and reliable, resulting in (R)-propylene carbonate in approximately 60% overall yield with ≥98% ee. Georg Thieme Verlag Stuttgart.
Cooperative NHC-based Catalytic System Immobilised onto Carbon Materials for the Cycloaddition of CO2 to Epoxides
Souleymanou, Myriam Y.,El-Ouahabi, Fatima,Masdeu-Bultó, Anna M.,Godard, Cyril
, p. 1706 - 1710 (2021)
New pyrene-tagged imidazolium salts and their corresponding carboxylates were synthesised and the latter tested as organocatalysts in the cycloaddition of CO2 with epoxides. The best performing organocatalyst was then non-covalently immobilised onto carbon materials (carbon nanotubes (CNTs), reduced graphene oxide (rGO) and carbon beads (CBs)) via π-π stacking interactions and their activity and recoverability in the cycloaddition reaction were studied. The heterogenised catalyst onto reduced graphene oxide (4 a@rGO) was recycled several times although a loss of activity was observed. This catalyst was also used for the transformation of a series of epoxides under mild conditions.
Highly regio- And stereoselective synthesis of cyclic carbonates from biomass-derived polyols: Via organocatalytic cascade reaction
Zhou, Hui,Zhang, Hui,Mu, Sen,Zhang, Wen-Zhen,Ren, Wei-Min,Lu, Xiao-Bing
supporting information, p. 6335 - 6341 (2019/12/03)
The cascade reaction of CO2, vicinal diols, and propargylic alcohol, was firstly achieved by dual Lewis base (LB) organocatalytic systems involving LB-CO2 adducts and commercially available organic amines. This methodology could overcome the chemical inertness of CO2, providing an alternative route to various functionalized five-membered cyclic carbonates in moderate to high yields under mild reaction conditions (25 °C, 1.0 atm of CO2). More importantly, this method could also be applied for facile and efficient synthesis of chiral polycyclic carbonates from biomass-derived polyols with complete configuration retention of chiral centers. This study provides an environment-friendly, scalable and cost effective protocol to construct value-added cyclic carbonates with multi-functional groups and chiral centers.
Chiral basket-handle porphyrin-Co complexes for the catalyzed asymmetric cycloaddition of CO2 to epoxides
Fu, Xiying,Jing, Xinyao,Jin, Lili,Zhang, Lilong,Zhang, Xiaofeng,Hu, Bin,Jing, Huanwang
, p. 997 - 1003 (2018/05/23)
The catalytic synthesis of cyclic carbonates via the cycloaddition of CO2 to epoxides is a standard methodology for CO2 fixation. For this purpose, chiral basket-handle porphyrin-Co complexes were devised, prepared, and fully characterized by nuclear magnetic resonance, mass spectrometry, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and specific rotation. The proposed metalloporphyrin catalysts were synthesized with either 1,1′-bi-2-naphthol or L-phenylalanine, which have different chirality, and then applied to the coupling of propylene oxide and CO2 for generating chiral cyclic carbonates with good enantioselectivity under extremely mild conditions in the presence of tetrabutyl ammonium chloride as a co-catalyst. The good enantioselectivity in the cycloaddition reaction is attributed to a synergistic interplay between the chiral porphyrin catalysts and the substrate. The mechanism and enantioselectivity of the asymmetric cycloaddition reaction is discussed.
