Chelate-Controlled Asymmetric Synthesis of 2-Substituted 2,3-Dihydropyridin-4(1H)-ones: Synthesis ofD- andL-aminodeoxyaltrose derivatives
作者:Jacques Streith、Arnaud Boiron、Jean-Louis Paillaud、Elsa-Maria Rodriguez-Perez、Christiane Strehler、Th�ophile Tschamber、Margareta Zehnder
DOI:10.1002/hlca.19950780106
日期:1995.2.8
Asymmetric methylation and phenylation of the chiral pyridinium salt 7, as well as methylation of chiral pyridinium salt 18, with Grignard reagents occurred in good yield and with good-to-excellent diastereoselectivities (Schemes 2 and 3, resp.). These results are best explained by assuming chelate control to govern the asymmetric alkylation/arylation process. The minimum-energy conformations of the
不对称甲基化和手性的吡啶鎓盐的苯基化7,以及手性的吡啶鎓盐的甲基化18,与格氏试剂发生在良好的产率和具有良好至优秀非对映选择性(方案2和3,RESP)。通过假定螯合剂控制非对称烷基化/芳基化过程,可以最好地解释这些结果。由“分子模拟Cerius-Dreiding II”程序确定的面外扭曲吡啶鎓盐7和18的最小能量构象与假定的不对称螯合物控制机制高度吻合。