Nucleophilic α‐Arylation and α‐Alkylation of Ketones by Polarity Inversion of N‐Alkoxyenamines: Entry to the Umpolung Reaction at the α‐Carbon Position of Carbonyl Compounds

A new aspect of enamine chemistry: The formation of N-alkoxyenamines from ketones has led to an efficient umpolung reaction. The alkylation of N-alkoxyenamines with trialkylaluminum compounds proceeded smoothly and gave α-alkylated ketones (see scheme). This reaction offers a simple transformation of ketones into α-substituted ketones without the need to isolate enamines and intermediary imines.