Synthesis of N-heterocycles via alkyne activation

Guido Verniest

Research output: Chapter in Book/Report/Conference proceedingMeeting abstract (Book)

Abstract

Because of the proven potential of gold catalyzed alkyne activation in heterocyclic chemistry, cyclization reactions of easily available alkynylated substrates such as propargylamides and -esters were evaluated to synthesize new N-heterocyclic compounds, such as 2 - 5. The gold catalyzed cycloisomerization of N-propargyl indole-2-carboxamides gave rise to beta-carbolinones, which were used as substrates for new analogues 2 of the antibiotic and antitumor compound Lavendamycin. In addition, silver nitrate mediated alkyne activation of N-propargyl-3-oxobutanamides and -esters successfully resulted in furan-fused pyrrolidinones and furanones 4. In some cases, no transition metal was necessary and alkyne activation by acids proved useful to synthesize heterocycles. Encouraged by the demonstrated value of propargylated amides and derivatives in heterocyclic chemistry, new synthetic pathways were evaluated towards propargylamines and -amides via copper catalyzed oxidative CH-alkynylation reactions in the presence of air. Although alkyne dimerization is known to occur under oxidative conditions in the presence of copper ions, it was shown that depending on the reaction conditions and the choice of copper salts, propargylamines could be obtained without formation of 1,3-diynes. In contrast, in the absence of amines as coupling partners, the copper catalyzed dehydrogenative coupling gave 1,3-diynes in good yields. Both classes of compounds are currently evaluated as substrates for gold-catalyzed transformation and proved to be promising substrates for the synthesis of heterocycles.
Original languageEnglish
Title of host publicationXXVth European Colloquium on Heterocyclic Chemistry
Publication statusPublished - 13 Aug 2012
EventUnknown -
Duration: 13 Aug 2012 → …

Conference

ConferenceUnknown
Period13/08/12 → …

Keywords

  • heterocyclic chemistry

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