Synthesis of 4, 6-dialkyl-1,3-dioxins. Versatile intermidiates for the preparation of (E)-alkenones, anti,anti-1, 2, 3-triols and syn-1, 3-diols

✍ Scribed by Raymond L Funk; Gary L Bolton

• Publisher: Elsevier Science
• Year: 1988
• Tongue: French
• Weight: 271 KB
• Volume: 29
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)86663-0

✦ Synopsis

The title compounds 4 are prepared from 4-alkyldioxins 2 via a metalation, alkylation sequence. The dialkyl dioxins 4 are thermally labile (providing enones) and undergo highly stereoselective hydroboration or hydrogenation reactions to provide enti,anti-1,2,3-triols and syn-1,3-diols, respectively. This methodology has been exploited in the synthesis of (i)-endo-l,3-dimethyl-2,9-dioxabicyclo[3.3.l]nonane.

We recently reported that the ally1 anion 1 represents an improvement in P-acyl vinyl anion (5) methodology.2 Thus, anion 1 is obtained by exclusive allylic deprotonation of readily available 4&1,3-dioxin3 with set-butyllithium and can be alkylated with a variety of electrophiles to provide monosubstituted dioxins 2. The dioxins 2 can then be thermally converted