RSS-Feed abonnieren
DOI: 10.1055/s-1994-25441
Syntheses of Substituted 6-Hydroxyhexenoic Acids and Related Tetrahydrofuran Systems by Metallocene-Template Directed 1,4-Selective Coupling of 1,3-Butadiene with Carbonyl Compounds
Publikationsverlauf
Publikationsdatum:
17. September 2002 (online)
![](https://www.thieme-connect.de/media/synthesis/199402/lookinside/thumbnails/10.1055-s-1994-25441-1.jpg)
Butadiene is 1,4-selectively coupled with a metal carbonyl and a ketone at the bis(η-cyclopentadienyl)zirconium template to yield the nine-membered metallacyclic products 3. Subsequent hydrolysis under oxidative conditions (pyridine N-oxide) gives the corresponding substituted 6-hydroxy-3-hexenoic acids 5. By this procedure a -CH2CH=CHCH2CO2H nucleophile has thus formally been added to the ketone substrate. Esterification of 5 followed by treatment with a base converts these organic template coupling products into substituted tetrahydrofuran acetic acids. Similarly, ketones are linearly coupled with butadiene and a nitrile to yield analogously structured hydroxyalkenones 15 which undergo acid catalyzed ring closure to yield the -CH2COR substituted tetrahydrofurans 16.