Self-assembled organic–inorganic hybrid silica with ionic liquid framework: a novel support for the catalytic enantioselective Strecker reaction of imines using Yb(OTf)3–pybox catalyst
作者:Babak Karimi、Aziz Maleki、Dawood Elhamifar、James H. Clark、Andrew J. Hunt
DOI:10.1039/c0cc01426e
日期:——
Yb(OTf)3âpybox is immobilized in a novel self-assembled ionic liquid hybrid silica and has been successfully applied as a catalyst for the asymmetric Strecker hydrocyanation of aldimines. This catalytic system can be reused for at least 6 times without any significant loss of activity and enantioselectivity.
A catalyticenantioselectiveStreckerreaction catalyzed by novel chiral lanthanum(III)−binaphthyl disulfonate complexes was developed. The key to promoting the reactions was a semistoichiometric amount of AcOH or i-PrCO2H, which takes advantage of HCN generation in situ. The corresponding cyanation products were obtained in high yields and with high enantioselectivities.
Described herein are compounds of formula (I), related compositions, and their use, for example in the formation of α-amino acids or a precursor thereof such as an α-aminonitrile.
Scaleable catalytic asymmetric Strecker syntheses of unnatural α-amino acids
作者:Stephan J. Zuend、Matthew P. Coughlin、Mathieu P. Lalonde、Eric N. Jacobsen
DOI:10.1038/nature08484
日期:2009.10
but it is still a challenge to obtain non-natural amino acids. Alkene hydrogenation is broadly useful for the enantioselective catalytic synthesis of many classes of amino acids, but it is not possible to obtain α-amino acids bearing aryl or quaternary alkyl α-substituents using this method. The Strecker synthesis—the reaction of an imine or imine equivalent with hydrogen cyanide, followed by nitrile
Oxazoline-Based Organocatalyst for Enantioselective Strecker Reactions: A Protocol for the Synthesis of Levamisole
作者:Arghya Sadhukhan、Debashis Sahu、Bishwajit Ganguly、Noor-ul H. Khan、Rukhsana I. Kureshy、Sayed H. R. Abdi、E. Suresh、Hari C. Bajaj
DOI:10.1002/chem.201302007
日期:2013.10.11
catalyze asymmetric Streckerreactions of various aromatic and aliphatic N‐benzhydrylimines with trimethylsilylcyanide (TMSCN) as a cyanide source at −20 °C to give α‐aminonitriles in high yield (96 %) with excellent chiral induction (up to 98 % ee). DFT calculations have been performed to rationalize the enantioselective formation of the product with the organocatalyst in these reactions. The organocatalyst