Reaction of Indole Carboxylic Acid/Amide with Propargyl Alcohols: [4+3]-Annulation, Unexpected 3-to 2-Carboxylate/Amide Migration, and Decarboxylative Cyclization

1-Methylindole-3-carboxamides react with substituted propargyl alcohols to afford lactams by [4 + 3]-annulation and carboxamide group migration to the indole-2-position. In contrast, indole-2-carboxylic acids/amides form fused seven membered lactones/lactams (oxepinoindolones/azepinoindolones) upon...

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Bibliographic Details
Published in:Organic letters Vol. 21; no. 14; pp. 5447 - 5451
Main Authors: Selvaraj, Karuppu, Debnath, Shubham, Swamy, K. C. Kumara
Format: Journal Article
Language:English
Published: WASHINGTON Amer Chemical Soc 19.07.2019
Subjects:
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
2-INDOLYLMETHANOLS
CASCADE REACTIONS
3-INDOLYLMETHANOLS
ANNULATION
ACIDS
TANDEM CYCLIZATION
STEREOSELECTIVE-SYNTHESIS
AZIDE CYCLOADDITION CHEMISTRY
ASYMMETRIC TOTAL-SYNTHESIS
ENANTIOSELECTIVE CONSTRUCTION
ISSN:1523-7060, 1523-7052
Online Access:Get more information
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Summary:1-Methylindole-3-carboxamides react with substituted propargyl alcohols to afford lactams by [4 + 3]-annulation and carboxamide group migration to the indole-2-position. In contrast, indole-2-carboxylic acids/amides form fused seven membered lactones/lactams (oxepinoindolones/azepinoindolones) upon treatment with substituted propargyl alcohols using catalytic Cu(OTf)(2). Decarboxylative cyclization of 1-methylindole-2- or indole-3-carboxylic acids with substituted propargyl alcohols under Lewis (for 1-methylindole-2-carboxylic acid) or Bronsted (for 1-methylindole-3-carboxylic acid) acid catalysis gives the same 3,4-dihydrocyclopentaindoles, demonstrating 3- to 2-carboxylate migration in the latter case.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.9b01686