title: Phase-transfer-catalyzed asymmetric alkylation of alpha-benzoyloxy-beta-keto esters: stereoselective construction of congested 2,3-dihydroxycarboxylic acid esters.
abstract: 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.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Keigo
authors.initials: K
authors.lastname: Sasaki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Fukumoto
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murase
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Abe
authors.forename: Takashi
authors.initials: T
authors.lastname: Ooi
authors.forename: Keiji
authors.initials: K
authors.lastname: Maruoka
mesh_terms: D000478:Alkylation; D002264:Carboxylic Acids / Q000138:chemical synthesis*; D002384:Catalysis; D004952:Esters / Q000138:chemical synthesis*; D007659:Ketones; D013237:Stereoisomerism
chemical_list: D002264:Carboxylic Acids; D004952:Esters; D007659:Ketones