A Multistep Rearrangement from 2,2-Disubstituted 1,3-Cyclohexanediones to 3-Substituted 2-Cyclohexenones via Phosphonate Anions and Its Application to a Formal Synthesis of (+/-)-α-Acoradiene

Article abstract of DOI:10.1021/jo00300a003

The reaction of 2,2-disubstituted 1,3-cyclohexanediones (1) with dimethyl methylphosphonate anion in the presence of trimethylsilyl chloride produces 3-substituted 2-cyclohexenones (2) in moderate to very good yields.This new overall reaction is accounted for by (a) attack of the phosphonate anion on a carbonyl group, (b) retro-aldol cleavage, (c) reorganization of the acidic proton, and (d) an intramolecular Wadsworth-Emmonds condensation.The new rearrangement is applied to a short synthesis of (+/-)-α-acoradiene.