Is amine addition vital for highly enantioselective hydrogenation of α,β-unsaturated carboxylic acid over cinchonidine-modified palladium?
作者:Tae Yeon Kim、Takashi Sugimura
DOI:10.1016/j.molcata.2010.05.013
日期:2010.7
Benzylamine (BA) is a commonly employed additive for the hydrogenation of α,β-unsaturatedacidsover the cinchonidine-modified palladium catalyst, but the BA addition effects largely depend on the reaction solvent. In toluene, BA is not required to obtain the high enantioselectivity. Quicker desorption of the product due to weaker acidity in toluene than in a commonly used wet dioxane reasonably explains
iron‐catalyzed synthesis of α,β‐unsaturated carboxylic acids from alkynes and carbondioxide was developed. This reaction proceeds through hydromagnesiation of alkynes followed by carbondioxide insertion under atmospheric pressure and ambient temperature in the presence of iron and a Grignard reagent as a catalyst and hydride source, respectively. Several symmetrical and unsymmetrical alkynes were transformed
Acceleration of Enantioselective Hydrogenation of Olefins over Pd/C by Cinchonidine as a Chiral Modifier. Comparison with Cinchonine, Pseudoenantiomer
作者:Takashi Sugimura、Hiroyuki Ogawa
DOI:10.1246/cl.2010.232
日期:2010.3.5
The performance of cinchonidine (CD) and cinchonine (CN) as chiral modifiers in enantioselective hydrogenation over Pd/C were compared in different concentrations. The catalytic hydrogenation with CD always occurred in better ee and at faster rate than that with CN. The difference is not attributable to the adsorption properties of the modifiers, but to the intrinsic enantio differentiation that accompanies the reaction acceleration.
Whereas thermal cyclisation of variously substituted 2,3-diarylacrylazides easily provided a new way to 3-aryl-isoquinolones, nitration of these compounds mainly led to corresponding 3-aryl-4-nitro-isoquinolones. After reduction into 4-amino-3-aryl-isoquinolones, amidification and subsequent cyclization gave the yet unknown title compounds.
Enantioselective hydrogenation of α,β-unsaturated carboxylic acid over cinchonidine-modified Pd nanoparticles confined in carbon nanotubes
作者:Zaihong Guan、Shengmei Lu、Can Li
DOI:10.1016/j.jcat.2013.10.010
日期:2014.3
We report the enantioselectivehydrogenation of α,β-unsaturatedacid catalyzed by Pd nanoparticles in carbon nanotubes (CNTs) taking the advantage of the channels as nanoreactors. The Pd nanocatalyst inside the channels of CNTs shows higher activity and enantioselectivity than that of Pd nanocatalyst outside the channels. As high as 92% enantioselectivity is achieved. The enhanced catalytic performance