Palladium(II)-Catalyzed Synthesis of α-Alkylidene-γ-butyrolactams from <i>N</i>-Allylic 2-Alkynamides. Total Synthesis of (±)-Isocynodine and (±)-Isocynometrine
作者:Xu Xie、Xiyan Lu、Yanyun Liu、Wei Xu
DOI:10.1021/jo001704u
日期:2001.10.1
actams via the Pd(II)-catalyzed cyclization of acyclic N-allylic 2-alkynamides via halopalladation, intramolecular olefin insertion, and beta-heteroatom elimination was developed. The reaction is less influenced by the leaving group and the concentration of the halide ions in comparison with the cyclization of acyclic alkynoates. The total syntheses of (+/-)-isocynodine and (+/-)-isocynometrine were
Palladium(II)-Catalyzed Asymmetric Synthesis of (<i>Z</i>)-α-Alkylidene-γ-butyrolactams from (<i>Z</i>)-<i>N</i>-Allylic 2-Alkynamides. Total Synthesis of (−)-Isocynometrine
作者:Wei Xu、Aidi Kong、Xiyan Lu
DOI:10.1021/jo060288w
日期:2006.5.1
Pd(OAc)2 combined with nitrogen-containing ligands catalyzed the cyclization of (Z)-N-allylic 2-alkynamides in acetic acid to afford the α-(Z)-acetoxyalkylidene-γ-butyrolactams in high yield and high stereoselectivity. When chiral nitrogen-containing ligands were used, the catalytic asymmetric protocol was achieved with moderate enantioselectivity (up to 80 °C). The utility of this new methodology
Eight imidazole alkaloids were isolated from Cynometra lujae: anantine, noranantine, cynometrine, isoanantine, isocynométrine, isocynodine, hydroxyanantine and cynolujine. The syntheses of isoanatine and isocynometrine were achieved starting from 1-methyl-5-methoxycarbonyl-imidazole and those of anantine and cynometrine starting from 1-methyl-4-methoxycarbonyl imidazole.