Syntheses of Highly Substituted Furan and Pyrrole Derivatives via Lithiated 3-Aryl-1-methoxyallenes: Application to the Synthesis of Codonopsinine
作者:Hans-Ulrich Reissig、Morshed Chowdhury
DOI:10.1055/s-2006-949622
日期:2006.9
with aldehydes, ketones, or imines to give allenyl ad- ducts, which cyclized to highly substituted heterocycles either un- der basic conditions or with silver nitrate assistance. Analogously, a dihydropyrrole derivative was obtained by the addition of anisyl- substituted lithiated methoxyallene derivative to an N-tosyl imine and subsequent cyclization of the intermediate. The two diaste- reomers obtained
锂化的 1-甲氧基-3-苯基丙二烯从苯基取代的炔丙醚原位生成。它们与醛类、酮类或亚胺类顺利结合得到烯丙基加合物,在碱性条件下或在硝酸银的帮助下,它们环化为高度取代的杂环。类似地,二氢吡咯衍生物通过将茴香基取代的锂化甲氧基丙二烯衍生物加成到N-甲苯磺酰基亚胺和随后的中间体环化而获得。随后将获得的两种非对映异构体转化为生物碱 (±)-codonopsinine 及其一种差向异构体。这些序列的关键步骤是甲硅烷基烯醇醚的高度非对映选择性硼氢化,定量导致羟基化中间体。