合成了基于手性大环salen配体的手性二聚大环V(V)salen配合物,该配体衍生自1 R,2 R -(-)二氨基环己烷与三醇双醛,并被评价为有效的催化剂(5 mol%),用于钾的不对称加成氰化物和三甲基甲硅烷基氰化物在-20°C时生成各种N-苄基亚胺。发现二聚手性大环赛伦络合物是一种有效的可循环催化剂,在2-甲氧基取代的N的情况下,可提供高产率(91%)的α-氨基腈和高手性诱导(ee可达99%)-苄基亚胺在16小时内。该催化体系在有机和无机氰化物来源下均能很好地工作,并且在保持对映选择性的情况下将催化剂循环使用多达五个循环。基于NMR研究和动力学,提出了催化对映选择性斯特雷克反应的可能机理。
<i>C</i><sub>2</sub>-Symmetric Recyclable Organocatalyst for Enantioselective Strecker Reaction for the Synthesis of α-Amino Acid and Chiral Diamine- an Intermediate for APN Inhibitor
作者:S. Saravanan、Arghya Sadhukhan、Noor-ul H. Khan、Rukhsana I. Kureshy、Sayed H. R. Abdi、Hari C. Bajaj
DOI:10.1021/jo300349f
日期:2012.5.4
Recyclable chiral amide-based organocatalyst 5 efficiently catalyzed asymmetric Streckerreaction of various aromatic and aliphatic N-benzhydrylimines with ethyl cyanoformate as cyanide source at −10 °C to give a high yield (95%) of α-aminonitriles with excellent chiral induction (ee, up to 99%) with the added advantage of recyclability. Based on experimental observations a probable mechanism was proposed
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