Fe‐Catalyzed Pictet‐Spengler‐Type Cyclization via Selective Four‐Electron Reductive Functionalization of CO 2

2021/02/08 by Wen‐Duo Li, Jie Chen, Dao‐Yong Zhu +1

paper · doi:10.1002/cjoc.202000521

Abstract

Main observation and conclusion Herein, we describe a novel catalytic Pictet‐Spengler‐type cyclization using CO 2 as a nontoxic and sustainable C1 feedstock with environmentally benign and non‐precious‐metal iron as catalyst. The reaction is achieved by selective four‐electron reduction of CO 2 into methylene level intermediate through carefully tuning the reaction parameters. A variety of tetrahydro‐β‐carbolines and other nitrogen‐containing heterocycles can be easily obtained under mild conditions. Mechanistic studies have shown that tetrahydro‐β‐carbolines are probably obtained via spiroindolenine intermediates.

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