title: Construction of chiral α-amino quaternary stereogenic centers via phase-transfer catalyzed enantioselective α-alkylation of α-amidomalonates.
abstract: An efficient enantioselective synthetic method for α-amido-α-alkylmalonates via phase-transfer catalytic α-alkylation was successfully developed. The α-alkylation of α-amidomalonates under phase-transfer catalytic conditions (50% KOH, toluene, -40 °C) in the presence of (S,S)-3,4,5-trifluorophenyl-NAS bromide afforded the corresponding α-amido-α-alkylmalonates in high chemical yields (up to 99%) and optical yields (up to 97% ee), which could be readily converted to versatile chiral intermediates bearing α-amino quaternary stereogenic centers. The synthetic potential of this methodology was demonstrated via the synthesis of chiral azlactone, oxazoline, and unnatural α-amino acid.
authors: †Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors: Min Woo
authors: MW
authors: Ha
authors: †Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors: Myungmo
authors: M
authors: Lee
authors: †Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors: Sujee
authors: S
authors: Choi
authors: †Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors: Seek
authors: S
authors: Kim
authors: †Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors: Suckchang
authors: S
authors: Hong
authors: ‡College of Pharmacy, Inje University, 607 Obang-dong, Gimhae, Gyeongnam 621-749, Korea.
authors: Yohan
authors: Y
authors: Park
authors: §College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 406-799, Korea.
authors: Mi-hyun
authors: MH
authors: Kim
authors: §College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 406-799, Korea.
authors: Taek-Soo
authors: TS
authors: Kim
authors: †Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors: Jihoon
authors: J
authors: Lee
authors: ∥Neuro-Medicine Center, Korea Institute of Science and Technology, PO Box 131, Cheongyang, Seoul 130-650, Republic of Korea.
authors: Jae Kyun
authors: JK
authors: Lee
authors: †Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors: Hyeung-geun
authors: HG
authors: Park