Direct Use of Phosphonium Salts for Alkylation of -Quinols: Formal α-Arylation of Carbonyls via a 5-Membered Betaine-Type Intermediate.

Unlike phosphonium ylides used extensively for C═C bond formation, herein we disclose the direct use of phosphonium salts for site-selective alkylation to -quinols via a 5-membered betaine-type intermediate. This strategy provides a novel and general approach for the synthesis of α-(-aminoaryl) esters, amides and ketones under ambient conditions. The reaction proceeds through in situ generation of P-ylide, alkylation and aromatization.