Stereoselective Synthesis of Cyclohepta[b]indoles by Visible-Light-Induced [2+2]-Cycloaddition/retro-Mannich-type Reactions

Xin-Peng Mu; Yuan-He Li; Nan Zheng; Jian-Yu Long; Si-Jia Chen; Bing-Yan Liu; Chun-Bo Zhao; Zhen Yang

doi:10.1002/anie.202101104

Stereoselective Synthesis of Cyclohepta[b]indoles by Visible-Light-Induced [2+2]-Cycloaddition/retro-Mannich-type Reactions

Angew Chem Int Ed Engl. 2021 May 10;60(20):11211-11216. doi: 10.1002/anie.202101104. Epub 2021 Apr 7.

Authors

Xin-Peng Mu¹, Yuan-He Li², Nan Zheng¹, Jian-Yu Long¹, Si-Jia Chen¹, Bing-Yan Liu¹, Chun-Bo Zhao¹, Zhen Yang^{1

2

3}

Affiliations

¹ State Key Laboratory of Chemical Oncogenomics and Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, P. R. China.
² Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education and Beijing National Laboratory for Molecular Science (BNLMS), Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, P. R. China.
³ Shenzhen Bay Laboratory, Shenzhen, 518055, P. R. China.

PMID: 33683807
DOI: 10.1002/anie.202101104

Abstract

A novel method for the concise synthesis of cyclohepta[b]indoles in high yields was developed. The method involves a visible-light-induced, photocatalyzed [2+2]-cycloaddition/ retro-Mannich-type reaction of enaminones. Experimental and computational studies suggested that the reaction is a photoredox process initiated by single-electron oxidation of an enaminone moiety, which undergoes subsequent cyclobutane formation and rapidly fragmentation in a radical-cation state to form cyclohepta[b]indoles.

Keywords: [2+2]/retro-Mannich-type cycloaddition; amine radical cation; cyclohepta[b]indole; photoredox catalysis.

Publication types

Research Support, Non-U.S. Gov't