Department of Chemistry, Wayne State University , 5101 Cass Avenue, Detroit, Michigan 48202, United States.
J Am Chem Soc. 2015 Feb 18;137(6):2243-6. doi: 10.1021/jacs.5b00243. Epub 2015 Feb 4.
Described herein is a short total synthesis of alkaloid (-)-205B (1) by means of an anti-selective SN2' alkylation of an attractively functionalized cyclopropanol and diastereoselective cyclization of the resulting aminoallene adduct for bicyclic ring formation. The synthesis features a general route to cis- or trans-2,6-disubstituted piperidines by lithium aluminum hydride reduction of the imine intermediate by an appropriate choice of solvent and cis- or trans-2,5-disubstituted pyrrolidines by an exceptional level of chirality transfer from a pendant allene. Particularly noteworthy are the brevity and convergence made possible by a segment-coupling strategy.
本文描述了通过对 attractively functionalized cyclopropanol 的反选择性 SN2' 烷基化以及所得氨基丙二烯加合物的非对映选择性环化反应，以形成双环环系，从而实现生物碱（-）-205B（1）的简短全合成。该合成方法的特点是通过适当选择溶剂，用锂铝氢还原亚胺中间体，得到顺式或反式 2,6-二取代哌啶；通过从侧链烯丙基中异常高水平的手性转移，得到顺式或反式 2,5-二取代吡咯烷。特别值得注意的是，通过分段偶联策略实现的简洁性和收敛性。
