Reaction of 6-(CF3)- and 6-(CH3)-2-(tert-Butyl)-1,3-dioxan-4-one Li Enolate with Two Equivalents of an Aldehyde – Unusual Reorganizations of Aldolates

✍ Scribed by Lapierre, Jean-Marc ;Gautschi, Markus ;Greiveldinger, Guy ;Seebach, Dieter

• Publisher: Wiley (John Wiley & Sons)
• Year: 1993
• Tongue: English
• Weight: 761 KB
• Volume: 126
• Category: Article
• ISSN: 0009-2940
• DOI: 10.1002/cber.19931261225

✦ Synopsis

Aldol addition / Transacetalization under basic conditions / Li aldolates / Li enolates and aldehydes, 1 :2 adducts The Li enolate of (2S,6R)-2-(tert-butyl)-6-trifluoromethyl-l,3-5-( l'-hydroxyethyl)-1,3-dioxan-4-one (7), another "strange" dioxan-4-one (1) reacts with isobutyraldehyde, pivalalde-aldol-type product resulting from one enolate and two aldehyde and cyclohexanecarboxaldehyde to give unexpected hyde molecules. There is an unusual reorganization involaldols [3a-5a, (l'R,2R,5R,6R)-2,6-dialky1-5-(2',2',2'-trifluo-ving a transacetalization process under basic conditions. The ro-l'-hydroxyethyl)-1,3-dioxan-4-ones]. The Li enolate of structures of two products (4a and 7 ) were determined by X-(2R,6R)-2-(tert-butyl)-6-methyl-l,3-dioxan-4-one (2) reacts ray crystallography, and a mechanism of formation is prowith pivalaldehyde to give (l'R,2S,5&6R)-2,6-di-(tert-butyl)-posed.