نتایج جستجو برای: aliphatic acids
تعداد نتایج: 271111 فیلتر نتایج به سال:
An unprecedented highly diastereoselective and enantioselective aldol reaction of α-alkyl azlactones and aliphatic aldehydes was achieved with cinchona alkaloid catalysts. To our knowledge, this reaction provides the first useful catalytic asymmetric access toward β-hydroxy-α-amino acids bearing alkyl substituents, which are structural motifs embedded in many natural products.
A ruthenium-catalyzed asymmetric arylation of aliphatic aldehydes and α-ketoesters with arylboronic acids has been developed, giving chiral alkyl(aryl)methanols and α-hydroxy esters in good yields. The use of a chiral bidentate phosphoramidite ligand (Me-BIPAM) achieved excellent enantioselectivities.
Thermoplastic polymers are currently prepared almost exclusively from fossil feedstocks. In view of the limited availability of such feedstocks, alternative renewable resources are desirable in the long term.[1.2] Polymer production from a renewable resource ideally allows for a complete molecular utilization of the feedstock and carries its molecular structure over into the resulting polymers,...
Suberin from the roots of carrots (Daucus carota), parsnip (Pastinaca sativa), rutabaga (Brassica napobrassica), turnip (Brassica rapa), red beet (Beta vulgaris), and sweet potato (Ipomoea batatas) was isolated by a combination of chemical and enzymatic techniques. Finely powdered suberin was depolymerized with 14% BF(3) in methanol, and soluble monomers (20-50% of suberin) were fractionated in...
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