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.
|Number of pages||3|
|Journal||Journal of Organic Chemistry|
|Publication status||Published - 1991|
ASJC Scopus subject areas
- Organic Chemistry