Free-radical-mediated [2 + 2 + 1] cycloaddition of acetylenes, amidines, and CO leading to five-membered α,β-unsaturated lactams

Takahide Fukuyama, Nao Nakashima, Takuma Okada, Ilhyong Ryu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

A free-radical-mediated [2 + 2 + 1] cycloaddition reaction comprising acetylenes, amidines, and CO was achieved by radical chain reaction to give five-membered α,β-unsaturated lactams in good yields. Both acyclic and cyclic amidines reacted with a variety of terminal acetylenes to afford monocyclic, bicyclic, and tricyclic lactams. We propose that vinyl radical carbonylation and nucleophilic addition of the amidine onto the resulting α-ketenyl radical give stable intermediates that are ready to undergo five-membered ring closure with elimination of tin radical.

Original languageEnglish
Pages (from-to)1006-1008
Number of pages3
JournalJournal of the American Chemical Society
Volume135
Issue number3
DOIs
StatePublished - 23 Jan 2013

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