Stereocontrolled Total Synthesis of (−)-Stemaphylline
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- 作者：Ana Varela ; Lennart K. B. Garve ; Dr. Daniele Leonori and Prof. Varinder K. Aggarwal
- 刊名：Angewandte Chemie International Edition
- 出版年：2017
- 出版时间：February 13, 2017
- 年：2017
- 卷：56
- 期：8
- 页码：2127-2131
- 全文大小：1806K
- ISSN：1521-3773
文摘
Homologation of readily available α-boryl pyrrolidines with metal carbenoids is especially challenging even when good leaving groups (Cl<sup>−sup>) are employed. By performing a solvent switch from Et<sub>2sub>O to CHCl<sub>3sub>, efficient 1,2-metalate rearrangement of the intermediate boronate occurs with both halide and ester leaving groups. The methodology was used in the total synthesis of the Stemona alkaloid (−)-stemaphylline in just 11 steps (longest linear sequence), with high stereocontrol (>20:1 d.r.) and 11 % overall yield. The synthesis also features a late-stage lithiation–borylation reaction with a tertiary amine containing carbenoid.