Tin-catalyzed conversion of trioses to alkyl lactates in alcohol solution
作者:Yukiko Hayashi、Yoshiyuki Sasaki
DOI:10.1039/b501964h
日期:——
Tin chlorides, SnCl2 and SnCl4.5H2O are excellent catalysts for the reactions of trioses, dihydroxyacetone and glyceraldehyde with alcohols (MeOH, EtOH and nBuOH) to give alkyl lactates, whose reaction mechanism involves the intermediary formation of pyruvicaldehyde followed by its esterification, which is distinctively promoted by tin halides.
The enantioselective hydrogenation of a variety of α-keto acetals to the corresponding α-hydroxy acetals with Pt catalysts modified with cinchonidine derivatives is described with ees up to 97% and high reaction rates, and the influence of the substrate structure, the modifier and the reaction conditions (catalyst, solvent, temperature, pressure, modifier concentration) was investigated in some detail.
Highly efficient and recyclable chiral Pt nanoparticle catalyst for enantioselective hydrogenation of activated ketones
作者:Xiuru Xue、Pu Chen、Peng Xu、Yanhua Wang
DOI:10.1016/j.catcom.2018.03.012
日期:2018.5
phase-separable chiral Pt nanoparticle catalyst exhibited excellent ee (>99%) in the enantioselectivehydrogenation of activated ketones for preparing chiral α-hydroxy acetals and chiral 1,2-diols. More importantly, the chiral catalyst could be easily separated by phase separation and directly reused in the next cycle without any loss in catalytic activity and enantioselectivity, even in the gram-scale reaction
Reactions of alcohols with α-alkoxyacroleins at room temperature
作者:N. A. Keiko、Yu. A. Chuvashev、L. G. Stepanova、M. G. Voronkov
DOI:10.1007/bf02641546
日期:1998.12
medium at 20°C under kinetically controlled conditions is the Markovnikoff addition at the C=C bond to form 2,2-dialkoxypropanals (methylglyoxal ketals). Under conditions of thermodynamic control, subsequent acetalization of the aldehyde group occurs to form 1,1,2,2-tetraalkoxypropanes. When the duration of the reaction is further increased in the absence of a water acceptor, the ketal group undegroes hydrolysis