Catalytic Diastereoselective [5 + 2] Annulation of N-Acryloyl Indoles with Cyclic Sulfonyl Enamides: Facile Access to Isoeburnamonine

Song Wei; Long Zheng; Sunewang R Wang; Yong Tang

doi:10.1021/acs.orglett.9b04556

Catalytic Diastereoselective [5 + 2] Annulation of N-Acryloyl Indoles with Cyclic Sulfonyl Enamides: Facile Access to Isoeburnamonine

Org Lett. 2020 Feb 7;22(3):1013-1017. doi: 10.1021/acs.orglett.9b04556. Epub 2020 Jan 23.

Authors

Song Wei¹, Long Zheng¹, Sunewang R Wang¹, Yong Tang¹

Affiliation

¹ State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , University of Chinese Academy of Sciences , 345 Lingling Lu , Shanghai 200032 , China.

PMID: 31971396
DOI: 10.1021/acs.orglett.9b04556

Abstract

ZnBr₂-catalyzed stereoselective [5 + 2] annulation of N-acryloyl indoles with cyclic sulfonyl enamides is reported, providing a concise and efficient synthesis of isoeburnamonine, which is the key intermediate for norvincamine. Both [2 + 2] and [4 + 2] cycloadducts, depending on the ring size of the enamides, have been shown to be the important intermediates for this [5 + 2] annulation.