Selective, one-pot synthesis of 2,3,6-trisubstituted pyridine and 2-cyclohexen-1-one derivatives from bicyclic ketals

✍ Scribed by Jong-Gab Jun; Tae Hee Ha

• Publisher: Journal of Heterocyclic Chemistry
• Year: 1997
• Tongue: English
• Weight: 314 KB
• Volume: 34
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570340151

✦ Synopsis

Abstract

Boron difluoromethanesulfonate, prepared from 5 equivalents of trimethylsilyl methanesulfonate and 1 equivalent of boron trifluoride etherate, has proved to be an active Lewis acid catalyst for the one‐pot transformation reaction of bicyclic ketals in the 6,8‐dioxabicyclo[3.2.1]octane series to 2,3,6‐trisubstituted pyridine or 2‐cyclohexen‐1‐one selectively, depending on conditions. A 1,5‐diketone was the reaction intermediate for both products. Pyridine was formed selectively by using a nitrile as a solvent or a reagent, but cyclohexenone was prepared in methylene chloride instead of a nitrile.