Stereoselective synthesis of trisubstituted α,β-unsaturated esters and amides via reactions of tantalum-alkyne complexes derived from acetylenic esters and amides with carbonyl compounds

Kazuhiko Takai, Makoto Tezuka, Kiitiro Utimoto

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Treatment of acetylenic esters with low-valent tantalum (TaCl5 and Zn) in DME and benzene produces tantalum-alkyne complexes (not isolated), which react with carbonyl compounds regioselectively at the α-position of the esters to give Z isomers of trisubstituted α,β-unsaturated esters in a stereoselective manner. In contrast, tantalum-alkyne complexes derived from acetylenic amides react with carbonyl compounds at the β-position of the amides predominantly.

Original languageEnglish
Pages (from-to)5980-5982
Number of pages3
JournalJournal of Organic Chemistry
Issue number21
Publication statusPublished - 1991
Externally publishedYes


ASJC Scopus subject areas

  • Organic Chemistry

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