Tuning the Reactivity of Isocyano Group: Synthesis of Imidazoles and Imidazoliums from Propargylamines and Isonitriles in the Presence of Multiple Catalysts
作者:Shuo Tong、Qian Wang、Mei-Xiang Wang、Jieping Zhu
DOI:10.1002/anie.201410113
日期:2015.1.19
tert‐butylisonitrile in the presence of a catalytic amount of both Yb(OTf)3 and AgOTf afforded imidazoles, whereas the same reaction with primary and secondary alkylisonitriles, as well as arylisonitriles, in the presence of three metal salts [Yb(OTf)3/AgOTf/KOTf] resulted in the 1,3,4,5‐tetrasubstituted imidazoliums in excellent yields. Both chiral amines and chiral isonitriles can be used to provide corresponding
在催化量的Yb(OTf)3和AgOTf的存在下,炔丙基胺与叔丁基异腈的反应得到了咪唑,而在三种金属盐的存在下,伯,仲烷基异腈以及芳基异腈的反应相同。 [Yb(OTf)3 / AgOTf / KOTf]产生1,3,4,5-四取代的咪唑类,产率极高。手性胺和手性异腈均可用于提供相应的手性杂环而没有外消旋作用。在这种多催化体系中,Yb(OTf)3催化了异腈向N的插入胺的H键,AgOTf催化所得的am氮与拴系的三键的5-exo-dig环化反应,而KOTf促进了盐的复分解,从而同时提供了对咪唑鎓的抗衡离子。根据常识,异氰基在这些反应中起极化三键的作用,而不是常规的卡宾样功能。