- Optical enrichment in enzyme-catalyzed resolution of 1-aryl-2,2-dimethyl-1,3-propanediols
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Novozym 435 efficiently catalyzed the chemo-, regio-, and enantioselective transesterification of 1-aryl-2,2-dimethyl-1,3-propanediols in different organic solvents with vinyl acetate as the acetyl donor at room temperature. This enzyme-catalyzed chemical
- Mukherjee, Chandrani,Mohapatra, Prabhu P.,Youssef, Dani,Jha, Amitabh
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- Lithium acetate-catalyzed crossed aldol reaction between aldehydes and trimethylsilyl enolates generated from other aldehydes
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Crossed aldol reaction between aromatic aldehydes having an electron-withdrawing group and trimethylsilyl enolates generated from several aldehydes proceeded smoothly in dry or water-containing DMF in the presence of a catalytic amount of a Lewis base such as lithium acetate or lithium benzoate. Successive reduction of the produced aldehydes with sodium borohydride (NaBH4) afforded the corresponding 1,3-diols in good to high yields in one-pot. Copyright
- Kawano, Yoshikazu,Fujisawa, Hidehiko,Mukaiyama, Teruaki
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p. 614 - 615
(2007/10/03)
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- The Design of Resolving Agents. Chiral Cyclic Phosphoric Acids
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A systematic investigation has been started with the twofold purpose of synthesizing efficient resolving agents and of gaining an insight into the factors that contribute to successful resolutions.We report on the synthesis, resolution, and application of a number of chiral cyclic phosphoric acids.Among these acids, 4-(2-chlorophenyl)-5,5-dimethyl-2-hydroxy-1,3,2-dioxaphosphorinane 2-oxide (7A) is an efficient resolving agent, being useful for the resolution of amines and amino acids.Acid chloride 20 is a useful reagent for the determination of the ee of chiral amines.The absolute configuration of (-)-7A was determined through an X-ray structure determination of its salt with (-)-(p-hydroxyphenyl)glycine.
- Hoeve, Wolter ten,Wynberg, Hans
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p. 4508 - 4514
(2007/10/02)
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