A catalyst-controlled chemoselective reaction of o-aminocinnamate and isothiocyanates in the presence of lanthanide complexes under mild and solvent-free conditions was developed. 2-Amino-3,1-benzothiazines were obtained in high yields when the reactions were catalyzed by Yb(OTf)3, whereas those catalyzed by [(Me3Si)2N]3La(μ-Cl)Li(THF)3 afforded 3,4-dihydroquinazoline-2-thiones in high to excellent yields. The mechanism for the product selectivity and high efficiency of the reaction was proposed.
在温和且无溶剂的条件下,在
镧系
金属配合物的存在下,开发了邻
氨基
肉桂酸和异
硫氰酸酯的催化剂控制的
化学选择性反应。当反应由Yb(OTf)3催化时,2-
氨基-3,1-苯并
噻嗪的产量很高,而由[(Me3Si)2N]3La(μ-Cl)Li(THF)3催化时,3,4-二氢
喹唑啉-2-
硫酮的产量很高。提出了产品选择性和反应高效率的机理。