Electroreduction of 3-bromo- and 3, 3-dichloro-β-lactams 1 carried out at the potential of the first voltammetric peak and in the presence of acetic anhydride gives 3-acetyl-β-lactams 2. The electrosynthesis is highly stereoselective, as only the acetyl derivative with trans configuration is formed.
catalyzes the enantioselective1,3-dipolarcycloaddition reaction of nitrones with propioloylpyrazole and acryloylpyrazole derivatives. The asymmetric environment created by intramolecular π-cation interaction gives the corresponding adducts in high yields with excellent enantioselectivity. This is the first successful method for the catalytic enantioselective1,3-dipolarcycloaddition of nitrones with acetylene
3-(2-萘基)-l-丙氨酸酰胺的手性铜 (II) 配合物成功催化硝酮与丙炔基吡唑和丙烯酰吡唑衍生物的对映选择性 1,3-偶极环加成反应。由分子内 π-阳离子相互作用产生的不对称环境以高产率提供相应的加合物,并具有出色的对映选择性。这是硝酮与乙炔衍生物的催化对映选择性 1,3-偶极环加成反应的第一个成功方法。1,3-偶极环加合物可以通过使用 SmI(2) 还原裂解 NO 键而立体选择性地转化为 β-内酰胺。
Yamamoto, Yutaka; Watanabe, Yokiyoshi, Chemical and pharmaceutical bulletin, 1987, vol. 35, # 5, p. 1871 - 1879
作者:Yamamoto, Yutaka、Watanabe, Yokiyoshi
DOI:——
日期:——
Masayuki, Sato; Ogasawara, Hiromichi; Yoshizumi, Eriko, Chemical and pharmaceutical bulletin, 1983, vol. 31, # 6, p. 1902 - 1909
Diazo- and Transition-Metal-Free CH Insertion: A Direct Synthesis of β-Lactams
作者:Luis F. R. Gomes、Luís F. Veiros、Nuno Maulide、Carlos A. M. Afonso
DOI:10.1002/chem.201404990
日期:2015.1.19
Carbene intermediates are very useful species for a range of reactions including CHinsertions and cycloadditions. They are most commonly generated by metal‐catalyzed release of nitrogen gas from diazo precursors. Herein, we present a novel CHinsertion of simple β‐ketoamide substrates, through reaction with (diacetoxyiodo)benzene (DIB) in the presence of a base. This unprecedented transformation