Abstract
A series of tungsten-eta(1)-alkynols tethered with a dimethylacetal, methyl ketone, or trimethoxymethane group are prepared. Treatment of these functionalized tungsten-alkynols with BF(3).Et(2)O leads to intramolecular cycloalkenation, producing bicyclic tungsten-oxacarbeniums in high yields. Air oxidation of these oxacarbenium salts produces unsaturated bicyclic lactones in good yields. The lactone products include delta- and epsilon-lactones fused with five-, six- and seven-membered carbocyclic rings. The preceding bicyclic tungsten-eta(1)-oxacarbeniums are highly reactive toward organocuprates, Grignard reagents, and diazomethane, leading to demetalation to give various derivatives of bicyclic lactones. A short synthesis of (+/-)-mitsugashiwalactone is developed based on this method.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
