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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 22, Number 9
BKCSDE 22(9)
September 20, 2001 

 
Title
Phase Transfer Catalyst (PTC) Catalyzed Alkylations of Glycinamides for Asymmetric Syntheses of α-Amino Acid Derivatives
Author
Yong Sun Park, Hyun Ju Kim, Dongyeol Lim
Keywords
Phase transfer catalyst, Amino acids, Chiral auxiliary, Crown ether, Alkylation.
Abstract
The chiral amine auxiliary mediated stereoselective alkylation reactions of glycinamides 1-6 and 15-17 using phase transfer catalyst (PTC) for liquid-solid extraction are described. The secondary N-(diphenylmethylene) glycinamides 1, 2 and 3 give better selectivities and yields than tertiary N-(diphenylmethylene) glycinamides 4, 5 and 6. Alkylation of the glycinamide 1 and 2 using 18-Crown-6 as a PTC in toluene at -40℃ gives best selectivities and yields. Alkylations of N-(4-chlorophenylmethylene)glycinamides 15, 16 and 17 under same PTC conditions give α, α-disubstituted amino acid derivatives 18, 19 and 20 with low diastereoselectivities.
Page
958 - 962
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