Lewis Acid Induced α-Alkylation of Carbonyl Compounds

Carbonyl compounds undergo α-alkylation via the corresponding silyl enol ethers using S_N1 active alkyl halides or acetates in the presence of Lewis acids. This methodology extends the scope of carbonyl chemistry considerably, since S_N1 active alkylating agents are generally base sensitive and therefore unsuitable for reactions with enolate anions or nitrogen analogs. A prime example is the α-tert-alkylation of aldehydes, ketones and esters.