One-Pot Synthesis of 3-Functionalized (Z)-Silyl Enol Ethers from 1-Arylallylic Alcohols by C,O-Difunctionalization of Dipotassio α,β-Dianion Intermediates

Previously reported syntheses of 3-functionalized silyl enol ethers using allyloxysilanes are hindered by undesirable reactions owing to retro Brook rearrangements. In this study, various 3-functionalized (Z)-silyl enol ethers were synthesized from readily available 1-arylallylic alcohols using (trimethylsilyl)methylpotassium as a base. C,O-Difunctionalization of the in-situ-generated dipotassio α,β-dianion with electrophiles and silyl chlorides is the key to the success of this transformation. Control experiments confirmed that the dianion has higher nucleophilicity and thermal stability than related siloxyallylpotassiums.