Stereoselective synthesis of flavonoids. Part 4. Trans- and cis-dihydroflavonols

✍ Scribed by Hendrik van Rensburg; Pieter S. van Heerden; Barend C.B. Bezuidenhoudt; Daneel Ferreira

• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 561 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(97)00916-2

✦ Synopsis

Epoxidation of a series of poly-oxygenated chalcones with H202 in the presence of poly-ctaminoacids yielded chiral aromatic oxygenated oxiranes in moderate to high optical yields. Lewis acid-catalysed phenylmethanethiol ringopening of the epoxide functionality and subsequent formation of the pyranone heterocycle, afforded trans-and cis-dihydroflavonols in moderate to high enantiomeric excess and yield.