Asymmetric Synthesis of a New Salen Type-titanium Complex as the Catalyst for Asymmetric Trimethylsilylcyanation of Aldehydes
作者:Zheng-Chang Lin、Chinpiao Chen
DOI:10.1002/jccs.201000101
日期:2010.8
This work describes the asymmetric synthesis of a new salen‐type ligand via a Diels‐Alder reaction and Curtius rearrangement. The ligand with a norbornane skeleton was used in the trimethylsilylcyanation of aldehydes, but the enantioselectivity was 55%ee. The norborane skeleton was cleaved to destroy this rigidity, and the eanatioselectivity was thereby increased to 85%ee.
A new (R)-hydroxynitrile lyase from Prunus mume: asymmetric synthesis of cyanohydrins
作者:Samik Nanda、Yasuo Kato、Yasuhisa Asano
DOI:10.1016/j.tet.2005.08.105
日期:2005.11
A new hydroxynitrile lyase (HNL) was isolated from the seed of Japanese apricot (Prunus mume). The enzyme has similar properties with HNL isolated from other Prunus species and is FAD containing enzyme. It accepts a large number of unnatural substrates (benzaldehyde and its variant) for the addition of HCN to produce the corresponding cyanohydrins in excellent optical and chemical yields. A new HPLC
Asymmetric Addition of Hydrogen Cyanide to Substituted Benzaldehydes Catalyzed by a Synthetic Cyclic Peptide,<i>Cyclo</i>((<i>S</i>)-phenylalanyl-(<i>S</i>)-histidyl)
Using cyclo((S)-phenylalanyl-(S)-histidyl) as catalyst, opticallyactive cyanohydrins from substituted benzaldehydes with p-methyl, m-methyl, o-methyl, m-methoxyl, or m-phenoxyl group were obtained with optical yield of 82–33%. For the asymmetric cyanohydrin synthesis, nonpolar solvent such as benzene or carbon tetrachloride was advantageous, while no asymmetricsynthesis took place in methanol or
Enantioselective cyanosilylation of aldehydes catalyzed by a multistereogenic salen–Mn(<scp>iii</scp>) complex with a rotatable benzylic group as a helping hand
A multistereogenic salen–Mn(iii) complex bearing an aromatic pocket and two benzylic groups as helping hands was found to be efficient in the catalysis of asymmetric cyanosilylation.