126838-29-7Relevant academic research and scientific papers
Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands
Mimura, Shohei,Mizushima, Sho,Sawamura, Masaya,Shimizu, Yohei
, p. 537 - 543 (2020/05/14)
A chiral phenol–NHC ligand enabled the copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters. The phenol moiety of the chiral NHC ligand played a critical role in producing the enantiomerically enriched products. The catalyst worked well for various (Z)-isomer substrates. Opposite enantiomers were obtained from (Z)- and (E)-isomers, with a higher enantiomeric excess from the (Z)-isomer.
Cascade Synthesis of 4-Arylcoumarins: Pd-Catalyzed Arylations and Cyclizations with (E)-Ethyl 3-(2-Hydroxyaryl)acrylates and Triarylantimony Difluorides
Kitamura, Yuki,Matsumura, Mio,Kato, Yukari,Murata, Yuki,Yasuike, Shuji
supporting information, p. 1652 - 1657 (2020/03/05)
Herein, we describe a simple general method for the synthesis of 4-arylcoumarins using pentavalent organoantimony compounds. The reactions of 3-(2-hydroxyaryl)acrylates with triarylantimony difluorides in the presence of Pd(OAc)2 (10 mol-%) and 2,2'-bipyridyl (10 mol-%) at 80 °C under aerobic conditions afforded 4-arylcoumarins in good-to-excellent yields. This protocol involves a cascade oxidative Heck-type arylation followed by cyclization, with all the aryl groups in the triarylantimony difluoride transferred to the coupling products. Triarylantimony difluorides resulted in better outcomes than those obtained with other pentavalent organoantimony or bismuth compounds.
Controlled mono- and double-Heck reaction catalyzed by a dicarbene dipalladium complex
Li, Yunfei,Liu, Gang,Cao, Changsheng,Wang, Shuzhan,Li, Yuling,Pang, Guangsheng,Shi, Yanhui
, p. 6241 - 6250 (2013/07/27)
The phosphine-free mono- and double-Heck reaction of terminal olefins with electron-deficient and electron-rich aryl halides (iodides and bromides) is described. These reactions are catalyzed by the dicarbene dipalladium complex 1 by controlling the stoichiometry of the aryl halide and the olefine, the loading of the palladium catalyst, as well as using different base, and with or without additive. The procedure of double-Heck reaction allows β,β- diarylation and β,β′-diarylation of terminal olefins and affords trisubstituted olefins in good to excellent yields.
Rhodium(I)-catalyzed enantioselective hydrogenation of substituted acrylic acids with sterically similar β,β-diaryls
Li, Yang,Dong, Kaiwu,Wang, Zheng,Ding, Kuiling
supporting information, p. 6748 - 6752 (2013/07/26)
Distinct differentiation: β,β-Disubstituted acrylic acids with sterically similar geminal diaryl groups can be hydrogenated with excellent enantioselectivities in the presence of a RhI complex formed in situ with two-component ligands, a chiral secondary phosphine oxide (SPO) and an achiral phosphine (Ph3P). The sense of asymmetric induction was found to be controlled by the substrate configuration, thus allowing access to both enantiomers of the product with the same catalyst. Copyright
Enantioselective synthesis of optically active 3,3-diarylpropanoates by conjugate hydrosilylation with chiral Rh-bis(oxazolinyl)phenyl catalysts
Itoh, Kengou,Tsuruta, Ayae,Ito, Jun-Ichi,Yamamoto, Yoshihiko,Nishiyama, Hisao
, p. 10914 - 10919 (2013/02/22)
Conjugate hydrosilylation of 3,3-diarylacrylate derivatives catalyzed by chiral rhodium-bis(oxazolinyl)phenyl complexes (1 mol %) at 60 C for 2 h was investigated to prepare optically active 3,3-diarylpropanoate derivatives in high yields up to 99% yield and high enantioselectivities up to 99%.
The Heck arylation of mono- and disubstituted olefins catalyzed by palladium supported on alumina-based oxides
Mieczyńska, Ewa,Gniewek, Andrzej,Pryjomska-Ray, Iweta,Trzeciak, Anna M.,Grabowska, Hanna,Zawadzki, Miros?aw
scheme or table, p. 195 - 205 (2011/10/30)
Palladium catalysts containing Pd(0) or Pd(II) supported on alumina-based mixed oxides prepared by alkoxide sol-gel method (Al2O3, Al2O3-ZrO2, Al2O3- ZrO2-Eu2O3, Al2O3-MgO, Al2O3-CeO2, Al2O3-Fe 2O3) are very effective in the Heck coupling of bromobenzene with butyl acrylate in DMF solvent. In the presence of an excess of bromobenzene, butyl cinnamate (1) was formed as the main product after 4 h. With the same catalysts, good results, up to 97% yield of ethyl β-phenylcinnamate (3), were also obtained in the coupling of bromobenzene with ethyl cinnamate. The three most active catalysts, Pd(0)/Al 2O3, Pd(II)/Al2O3, and Pd(II)/Al2O3-Fe2O3, were applied in the Heck cross-coupling of cinnamates with different bromobenzene and iodobenzene derivatives, leading to β-arylcinnamate products. The highest yield was observed when iodoanisole and cinnamic aldehyde were used as substrates. The formation of Pd(0) nanoparticles in the Heck reaction carried out with supported Pd(II) catalyst precursors was confirmed by TEM measurements.
Chiral dihydrobenzo[1,4]oxazines as catalysts for the asymmetric transfer-hydrogenation of α,β-unsaturated aldehydes
Ebner, Christian,Pfaltz, Andreas
supporting information; experimental part, p. 10287 - 10290 (2012/02/01)
A new class of organocatalysts based on the structure of 2,3-dihydrobenzo[1,4]oxazine was prepared and applied in the enantioselective transfer-hydrogenation of α,β-unsaturated aldehydes with Hantzsch ester as hydride donor. These catalysts proved to be particularly effective for the conjugate reduction of β,β-diaryl-substituted acrylaldehydes leading to saturated aldehydes bearing a stereogenic center with two different aryl groups with enantioselectivities of up to 91% ee.
Development of a palladium catalyzed addition of boronic acids to alkynyl esters: synthesis of trisubstituted olefins as single isomers
Bush, Alexander Graham,Jiang, Jojo Liu,Payne, Philippa R.,Ogilvie, William W.
scheme or table, p. 8502 - 8506 (2010/01/06)
Very small phosphine ligands allow access to single isomer trisubstituted olefins from alkynyl esters with complete control of both stereochemistry and regiochemistry. This method provides a convenient synthesis of single isomer trisubstituted olefins wit
