Formation of Highly Substituted Indenes through Acid Promoted Cyclodehydration with Nucleophile Incorporation

Annaliese S. Dillon, Daniel J. Kerr, Bernard L. Flynn

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Readily accessible 3-aryl-2-carboxypropenones (by Knoevenagel condensation) undergo acid promoted cyclodehydration with nucleophile incorporation to form highly substituted indenes. For stronger nucleophiles, nucleophile incorporation precedes cyclodehydration in a nucleophilic-addition-cyclodehydration (NAC) sequence. For weaker nucleophiles, cyclodehydration precedes nucleophile incorporation in a cyclodehydrative-nucleophilic-trapping (CNT) sequence, involving a reactive allyl cation intermediate. The substrate scope and preferred cyclization pathway (NAC or CNT) has been studied with respect to 3-aryl-2-carboxypropenone and the nature of the nucleophile. Also, for 1,3-diaryl-2-carboxypropenones, which can also undergo Nazarov cyclization, delineation between competing Nazarov and CNT pathways is controlled by the nature of the acid catalyst.

Original languageEnglish
Pages (from-to)2756-2767
Number of pages12
JournalThe Journal of Organic Chemistry
Volume84
Issue number5
DOIs
Publication statusPublished - 1 Mar 2019

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