N-Benzylamides were debenzylated efficiently with 4 equiv. of p-TsOH in refluxing toluene. Good to quantitative yields of the desired primary amides were obtained within 2-4 h from a wide variety of N-2,4-dimethoxybenzylamides. N-4-Methoxyl-benzyl amides and N-benzylamides were also debenzylated cleanly. In the case of N-2,4-dimethoxylbenzylamides, selective N-debenzylation was possible in the presence of N-Fmoc, N-t-BOC or N-trityl-protection. Protected amino acid amides survived these conditions without any detectable epimerization. (C) 2003 Elsevier Science Ltd. All rights reserved.
据报道,使用铱-亚磷酰胺络合物可以有效地不对称地氢化β,γ-不饱和γ-内酰胺。以优异的产率和对映选择性(高达99%的产率和99%的ee)获得手性γ-内酰胺。机理研究表明,还原产物是通过氢化由β,γ-不饱和γ-内酰胺生成的N-酰基亚胺阳离子而获得的,该产物已通过1 H NMR分析证实。反应在0.1mol%的降低的催化剂负载下进行,并且还原的产物可以转化为两种潜在的生物活性化合物。提供了合成手性γ-内酰胺的新途径。