Stereochemical course of the reductive spiroannulations of N-Boc and N-benzyl 2-cyanopiperidines
作者:Scott A. Wolckenhauer、Scott D. Rychnovsky
DOI:10.1016/j.tet.2005.01.099
日期:2005.3
The stereochemical outcome of spiroannulations of N-protected 2-lithiopiperidines (generated by lithium di-tert-butyl biphenylide (LiDBB) mediated reductive lithiation of 2-cyanopiperidines) was investigated using deuterium labeled side-chains containing phosphate leaving groups. High stereoselectivity was observed when benzyl (Bn) protected 2-cyanopiperidines were employed, while tert-butoxycarbonyl
使用氘标记的含有磷酸酯离去基团的侧链,研究了N保护的2-lithiopiperidines(由二叔丁基联苯锂(LiDBB)介导的2-cyanopiperidines还原锂化生成)的螺环奉的立体化学结果。当使用苄基(Bn)保护的2-氰基哌啶时,观察到高的立体选择性,而叔丁氧羰基(Boc)保护的2-氰基哌啶则提供较低的选择性。提出了一些模型来合理化这项研究的结果。