Synthesis of Amidines and Benzoxazoles from Activated Nitriles with Ni(0) Catalysts
作者:Jorge A. Garduño、Juventino J. Garcı́a
DOI:10.1021/acscatal.5b00348
日期:2015.6.5
Amidines and 2-substituted benzoxazoles were synthesized from N-heterocyclic nitriles under mild conditions (50 °C, 48 h, two steps) in an atom-economical process that involves addition of methanol, the solvent, to a nitrile moiety to yield a methyl imidate and the subsequent extrusion of solvent in the presence of amines to afford the title compounds. Methyl imidate formation was achieved by developing
脒和2-取代的苯并恶唑分别选自N合成-在温和的条件(50℃,48小时,两步)以原子经济的过程,涉及加入甲醇,溶剂的,对腈部分,得到甲基下杂环腈亚胺酸酯和随后在胺存在下的溶剂挤出,得到标题化合物。通过使用[(dippe)Ni(H)] 2(dippe = 1,2-双(二异丙基膦基)乙烷),[Ni(cod)2 ] / dppe或[Ni( cod)2 ] / P(OPh)3(cod = 1,5-环辛二烯,dppe = 1,2-双(二苯基膦基)乙烷,P(OPh)3=亚磷酸三苯酯)作为催化剂前体。关于配体,对于给定的底物,即4-氰基吡啶,对于σ供体双齿二元醇,Ni(0)催化体系的最佳性能被发现,而单齿π受体P(OPh)3的效率较低。关于底物,对于给定的Ni-dippe体系,位阻以及更重要的是,底物的吸电子特征控制亚氨酸盐的形成,从而控制am和苯并恶唑的收率。