Phase-Transfer-Catalyzed Asymmetric Alkylation of α-Benzoyloxy-β-keto Esters: Stereoselective Construction of Congested 2,3-Dihydroxycarboxylic Acid Esters
Highly enantioselective phase‐transfer‐catalyzed alkylation of tert‐butyl 2‐benzoyloxy‐3‐oxobutanoate was realized by the use of an N‐spiro chiral quaternary ammonium salt, as a complementary approach to the asymmetric hydroxylation of α‐alkyl‐β‐keto esters. The synthetic utility of the alkylated compounds is highlighted by the diastereoselective reduction and alkylation of the remaining ketone moiety