Phase-transfer-catalyzed asymmetric alkylation of alpha-benzoyloxy-beta-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 alpha-alkyl-beta-keto esters. The synthetic utility of the alkylated compounds is highlighted by the diastereoselective reduction and alkylation of the remaining ketone moiety to give various enantiomerically enriched congested 2,3-dihydroxycarboxylic acid esters.
Hashimoto
Takuya
T
Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502, Japan.
Sasaki
Keigo
K
Fukumoto
Kazuhiro
K
Murase
Yuichi
Y
Abe
Naoyuki
N
Ooi
Takashi
T
Maruoka
Keiji
K
D000478:Alkylation; D002264:Carboxylic Acids / Q000138:chemical synthesis*; D002384:Catalysis; D004952:Esters / Q000138:chemical synthesis*; D007659:Ketones; D013237:Stereoisomerism
D002264:Carboxylic Acids; D004952:Esters; D007659:Ketones