1009-67-2Relevant academic research and scientific papers
Gas-phase pyrolytic reaction of 3-phenoxy and 3-phenylsulfanyl-1-propanol derivatives: Kinetic and mechanistic study
Dib,Ibrahim,Al-Awadi,Ibrahim,Al-Awadi
, p. 51 - 58 (2008)
3-Phenoxy-l-propanols 1a-c and 3-phenylsuIfanyl-1-propanols 2a-c containing primary, secondary, and tertiary alcohols were prepared and subjected to gas-phase pyrolysis in a static reaction system. Pyrolysis of 4-phenyl-1-butanol 3, 2-methyl-3-phenyl-1-propanol 4, and 2-methyl-3-phenylpropanoic acid 5 was also studied, and results were compared with those obtained for compounds 1-3. The pyrolytic reactions were homogeneous and followed a first-order rate equation. Analysis of the pyrolysate showed the products to be phenol (from la to 1c), thiophenol (from 2a to 2c), and toluene (from 3 to 5) and carbonyl compounds. The kinetic results and product analysis of each of the nine investigated compounds are rationalized in terms of a plausible transition state for the elimination pathway.
Bifunctional Catalysts for Regioselective Hydrogenation and for Hydrogenation of Highly-substituted Alkenes
Preston, Sheila A.,Cupertino, Domenico C.,Palma-Ramirez, Pilar,Cole-Hamilton, David J.
, p. 977 - 978 (1986)
catalyses the hydrogenation of highly-substituted acrylic acids in the presence of base by a mechanism involving chelate stabilisation of alkene co-ordination and base-catalysed transesteification of the co-ordinated mixed anhydride; for hexa-2,4-dienoic acid, selective hydrogenation of the αβ double bond occurs.
Model Studies on the Enzyme-Regulated Stereodivergent Cascade Passerini Reaction
Brodzka, Anna,Koszelewski, Dominik,Ostaszewski, Ryszard,Samsonowicz-Górski, Jan,Wilk, Monika
, p. 4161 - 4165 (2021)
The synthesis of chiral α-acyloxy carboxamides containing two stereogenic centers continues to be a challenging field of organic chemistry. Herein, we have proposed and proved the feasibility of an enzyme regulated-cascade reaction, which using the same substrates enables the formation of individual stereoisomers of α-acyloxy carboxamides with up to 99 % ee. The access to the individual stereoisomeric products has been achieved by a combination of the enzymatic kinetic resolution of racemic vinyl esters, subsequent Passerini reaction, and enzymatic kinetic resolution of formed α-acyloxy carboxamides. The presented studies are promising in exploratory proof-of-concept of enzyme-controlled stereodivergent cascade to form an important class of chiral compounds for medicinal chemistry.
RHODIUM(I) COMPLEXES OF FERROCENYLPHOSPHINES AS EFFICIENT ASYMMETRIC CATALYSTS. THE STRUCTURE OF Fe(η5-C5H3(P(CMe3)2-1,3)(η5-C5H3(CHMeNMe2)(P(CMe3)2-1,2)
Appelton, Trevor D.,Cullen, William R.,Evans, Sthephen,Kim, Tae-Jeong,Trotter, James
, p. 5 - 22 (1985)
Rhodium(I) complexes of the chiral ligands Fe(η5-C5H5-n(P(CMe3)2)n-1,3)(η5-C5H3(CHMeNMe2)P(CMe3)2-1,2 (n=0-2) are P-N bound, and are asymmetric hydrogenation catalysts.The configuration of the product from prochiral olefins is controlled by the planar chirality of the ligand.The catalyst with n=2 is the most efficient affording optical yields as good as those obtained from more conventional systems embodying PAr2 donors.Crystals of the ligand n=2 are monoclinic, P21, a 11.448(4), b 44.667(7), c 8.669(3) Angsroem, β 111.98(1), V 4111(2) Angstroem, Z=4 (2 molecules per asymmetric unit) Dx 1.114, Dm 1.129 g cm-3 (by flotation in aqueous KI), final R=0.069 for 4799 observed reflections.The molecule is chiral, with an (S,S) configuration, and the two crystallographically independent molecules have almost identical geometries and conformations.The cyclopentadienyl rings are close to planar, deviate slightly from coplanarity, and are rotated by about 7 deg from an eclipsed conformation; the substituent P and C atoms are significantly displaced from the ring planes.Fe-C bond length average 2.044 and 2.092 Angstroem to unsubstituted C atoms, respectively.
New types of o-carborane-based chiral phosphinooxazoline (Cab-PHOX) ligand systems: Synthesis and characterization of chiral Cab-PHOX ligands and their application to asymmetric hydrogenation
Lee, Jong-Dae,Thanh, Thien Co,Kim, Tae-Jeong,Sang, Ook Kang
, p. 771 - 774 (2009)
o-Carborane-based chiral phosphinooxazoline (Cab-PHOX) ligands were synthesized for the first time and applied to the iridium- and rhodium-catalyzed hydrogenation of unfunctionalized and functionalized olefins with an enantioselectivity of up to 98% and 96%, respectively. The modularity of the Cab-PHOX ligands is highlighted by the facile preparation of a variety of sterically and electronically different ligands. Georg Thieme Verlag Stuttgart.
Ferrocenyl chiral bisphosphorus ligands for highly enantioselective asymmetric hydrogenation via noncovalent ion pair interaction
Chen, Caiyou,Wang, Heng,Zhang, Zhefan,Jin, Shicheng,Wen, Songwei,Ji, Jianjian,Chung, Lung Wa,Dong, Xiu-Qin,Zhang, Xumu
, p. 6669 - 6673 (2016)
A new class of ferrocenyl chiral bisphosphorus ligand, Wudaphos, was developed, and exhibits excellent ee and activity (ee up to 99%, TON up to 20000) for the asymmetric hydrogenation of both 2-aryl and 2-alkyl acrylic acids through ion pair noncovalent interaction under base free and mild reaction conditions. Well-known anti-inflammatory drugs such as naproxen and ibuprofen together with the intermediate for the preparation of Roche ester and some bioactive compounds were also efficiently obtained with excellent ee. Control experiments were conducted and revealed that the ion pair noncovalent interaction and chain length played important roles.
Enantioselective Hydrogenation of α-Methylcinnamic Acid over Pd/Al2O3: A Kinetic Study of Solvent, Temperature and Pressure Effects
Sun, Xiaojing,Monnier, John R.,Williams, Christopher T.
, p. 881 - 886 (2013)
The enantioselective hydrogenation of α-methylcinnamic acid (MCA) over cinchonidine modified 5 wt% Pd/Al2O3 was studied in a liquid batch reactor. Both the reaction activity and enantioselectivity towards the (R) product are strongly solvent dependent. The reaction is zero order in hydrogen pressure and first order in MCA. The presence of cinchonidine does not affect the reaction order with respect to either acid or H2 pressure, but has a significant inhibiting effect on the reaction rate. The catalyst exhibits stable activity during the reaction with no sign of deactivation. Graphical Abstract: [Figure not available: see fulltext.]
Regioselectivity inversion tuned by iron(iii) salts in palladium-catalyzed carbonylations
Huang, Zijun,Cheng, Yazhe,Chen, Xipeng,Wang, Hui-Fang,Du, Chen-Xia,Li, Yuehui
, p. 3967 - 3970 (2018)
Impactful regioselectivity control is crucial for cost-effective chemical synthesis. By using cheap and abundant iron(iii) salts, the hydroxycarbonylations of both aromatic and aliphatic alkenes were significantly enhanced in both reactivity and selectivity (iso/n or n/iso up to >99:1). Moreover, Pd-catalyzed carbonylation selectivity can be switched from branched to linear by using different Fe(iii) salts. In addition, similar results were obtained for the carbonylation of secondary alcohols.
COPPER-CATALYZED REACTION OF GRIGNARD REAGENTS WITH β-PROPIOLACTONES: A CONVENIENT METHOD FOR THE SYNTHESIS OF Β-SUBSTITUTED PROPIONIC ACIDS
Sato, Toshio,Kawara, Tatsuo,Kawashima, Masatoshi,Fujisawa, Tamotsu
, p. 571 - 574 (1980)
Grignard reagents react with β-propiolactones in the presence of a copper(I) catalyst to give β-substituted propionic acids in high yields.
A THREE CARBON HOMOLOGATION BY THE RING-OPENING OF β-PROPIOLACTONES WITH DIORGANOCUPRATES
Fujisawa, Tamotsu,Sato, Toshio,Kawara, Tatsuo,Kawashima, Masatoshi
, p. 2181 - 2184 (1980)
Various organocuprates react with β-propiolactones to give β-substituted propionic acids in high yields.
