Spiro-fused Pyrrolidine, Piperidine, and Oxindole Scaffolds from Lactams

Expedient routes to three classes of novel spiro-fused pyrrolidine, piperidine, and indoline heterocycle scaffolds are described. These three-dimensional frameworks, which conform to the “rule of three”, are suitably protected to allow for site-selective manipulation and functionalization. Different modes of substrate control were explored, which allow for good to excellent levels of diastereoselectivity and dispense with the need for additional chiral reagents or catalysts. The concepts developed were applied in short, formal syntheses of (±)-coerulescine and (±)-horsfiline.

本文报道了三类新型螺稠合吡咯烷（pyrrolidine）、哌啶（piperidine）及吲哚啉（indoline）杂环骨架的简便高效合成路线。此类三维骨架符合“三规则”，且经适当保护，可进行位点选择性操作与官能化修饰。本研究探索了多种底物控制模式，可获得良好至优异的非对映选择性，且无需额外使用手性试剂或催化剂。所开发的合成策略已应用于(±)-蓝堇色胺（coerulescine）与(±)-horsfiline的简短形式合成。