Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

Authors

Alireza Shakoori, University of WollongongFollow
John B. Bremner, University of WollongongFollow
Mohammed K. Abdel-Hamid, University of WollongongFollow
Anthony C. Willis, Australian National University
Rachada Haritakun, National Science and Technology Development Agency, Thailand
Paul A. Keller, University of WollongongFollow

RIS ID

101379

Publication Details

Shakoori, A., Bremner, J. B., Abdel-Hamid, M. K., Willis, A. C., Haritakun, R. & Keller, P. A. (2015). Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo. Beilstein Journal of Organic Chemistry, 11 481-492.

Abstract

Diversity-directed synthesis based on the cascade allylation chemistry of indigo, with its embedded 2,2'-diindolic core, has resulted in rapid access to new examples of the hydroxy-8a,13-dihydroazepino[1,2-a:3,4-b']diindol-14(8H)-one skeleton in up to 51% yield. Additionally a derivative of the novel bridged heterocycle 7,8-dihydro-6H-6,8a-epoxyazepino[1,2-a:3,4-b']diindol-14(13H)-one was produced when the olefin of the allylic substrate was terminally disubstituted. Further optimisation also produced viable one-pot syntheses of derivatives of the spiro(indoline-2,9'-pyrido[1,2-a]indol)-3-one (65%) and pyrido[1,2,3-s,t]indolo[1,2-a]azepino[3,4-b]indol-17-one (72%) heterocyclic systems. Ring-closing metathesis of the N,O-diallylic spiro structure and subsequent Claisen rearrangement gave rise to the new (1R,8aS,17aS)-rel-1,2-dihydro-1-vinyl-8H,17H,9H-benz[2',3']pyrrolizino[1',7a':2,3]pyrido[1,2-a]indole-8,17-(2H,9H)-dione heterocyclic system.