Bronsted-acid-mediated divergent reactions of betti bases with indoles: an approach to chromeno[2,3-b]indoles through intramolecular dehydrogenative C2-alkoxylation of indole

TitleBronsted-acid-mediated divergent reactions of betti bases with indoles: an approach to chromeno[2,3-b]indoles through intramolecular dehydrogenative C2-alkoxylation of indole
Publication TypeJournal Article
Year of Publication2016
AuthorsDeb, ML, Pegu, CDev, Deka, B, Dutta, P, Kotmale, AS, Baruah, PK
JournalEuropean Journal of Organic Chemistry
Issue20
Pagination3441-3448
Date PublishedJUL
ISSN1434-193X
KeywordsBetti bases, C-O bond formation, Dearylation, Fused-ring systems, nitrogen heterocycles
Abstract

Divergent reactions of various 1-(aminoalkyl) naphthols and 2-(aminoalkyl) phenols (commonly known as Betti bases) with indoles under Bronsted acid catalysis is reported. With the reaction strategies, one can efficiently synthesize important indole derivatives such as 3-(alpha,alpha-diarylmethyl)indoles and chromeno[2,3-b]indoles. Furthermore, we disclose here a new C-C bond-cleavage reaction, in which naphthol and phenol behave as leaving groups to produce diarylmethanes. Inexpensive reagents such as p-toluenesulfonic acid monohydrate and molecular iodine are used to catalyze the reactions. No metal catalyst is required. The starting material of the reactions, Betti bases, are easily prepared from a three-component reaction of naphthol/phenol, aldehydes, and secondary amines. The mechanisms for the reactions are established through some control experiments. Quinone methide is the key intermediate for all the reactions reported herein.

DOI10.1002/ejoc.201600546
Type of Journal (Indian or Foreign)

Foreign

Impact Factor (IF)3.068
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