Enantioselective synthesis of mixed 3,3'-bisindoles via a phosphine-catalyzed umpolung γ-addition of 3'-indolyl-3-oxindoles to allenoates

Yildiz Tasdan; Guang-Jian Mei; Yixin Lu

doi:10.1016/j.scib.2020.01.017

Enantioselective synthesis of mixed 3,3'-bisindoles via a phosphine-catalyzed umpolung γ-addition of 3'-indolyl-3-oxindoles to allenoates

Sci Bull (Beijing). 2020 Apr 15;65(7):557-563. doi: 10.1016/j.scib.2020.01.017. Epub 2020 Jan 23.

Authors

Yildiz Tasdan¹, Guang-Jian Mei², Yixin Lu³

Affiliations

¹ Department of Chemistry, National University of Singapore, Singapore 117543, Singapore.
² Department of Chemistry, National University of Singapore, Singapore 117543, Singapore. Electronic address: chmmeig@nus.edu.sg.
³ Department of Chemistry, National University of Singapore, Singapore 117543, Singapore; Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Fuzhou 359297, China; National University of Singapore (Suzhou) Research Institute, Suzhou Industrial Park, Suzhou 215123, China. Electronic address: chmlyx@nus.edu.sg.

PMID: 36659187
DOI: 10.1016/j.scib.2020.01.017

Abstract

An enantioselective umpolung γ-addition reaction of 3'-indolyl-3-oxindoles to allenoates catalyzed by amino acid-derived bifunctional phosphine catalysts has been developed. A wide range of chiral mixed 3,3'-bisindole scaffolds containing an all-carbon quaternary stereogenic center were obtained in high yields and with excellent enantioselectivities. 3,3'-Bisindoles are valuable synthetic intermediates, the employment of which led to formal total syntheses of (+)-Chimonanthine, (+)-Folicanthine and (-)-Calycanthine, as well as facile creation of useful pyrrolidinoindoline core structure.

Keywords: Allenoates; Amino acid-derived bifunctional phosphine; Formal total syntheses; Mixed 3,3′-Bisindole; Umpolung γ-addition.