A novel lanthanum triflate mediated conversion of N-benzyl­oxycarbonyl-, N-allyloxycarbonyl-, and N-trichloroethoxycarbonyl-­protected amines into nonsymmetric ureas was discovered. In this study, lanthanum triflate was found to be an effective catalyst for preparing various nonsymmetric ureas from protected amines. A variety of protected aromatic and aliphatic carbamates reacted readily with various amines in the presence of lanthanum triflate to generate the desired ureas in high yields. This result demonstrated that this novel lanthanum triflate catalyzed preparation of ureas from Cbz, Alloc, and Troc carbamates can be employed for the formation of various urea structures.

中文翻译：

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三氟甲磺酸镧 (III) 催化从 N-苄氧羰基-、N-烯丙氧羰基-和 N-2,2,2-三氯乙氧羰基保护的胺直接合成脲

发现了一种新型三氟甲磺酸镧介导的 N-苄氧羰基-、N-烯丙氧羰基-和 N-三氯乙氧羰基-保护的胺转化为非对称脲。在这项研究中，发现三氟甲磺酸镧是一种从受保护的胺制备各种非对称脲的有效催化剂。在三氟甲磺酸镧存在下，各种受保护的芳香族和脂肪族氨基甲酸酯很容易与各种胺反应，以高产率生成所需的尿素。该结果表明，这种由 Cbz、Alloc 和 Troc 氨基甲酸酯催化制备尿素的新型三氟甲磺酸镧可用于形成各种尿素结构。