The Dakin-West reaction of N-alkoxycarbonyl-N-alkyl-alpha-amino acids employing trifluoroacetic anhydride.
The Dakin-West reaction of N-alkoxycarbonyl-N-alkyl-alpha-amino acids (1a-j) with trifluoroacetic anhydride in the presence of pyridine gave alpha-amido trifluoromethyl ketones (2a-j), in which probable intermediates were mesoionic 1,3-oxazolium-5-olates (munchnones). The diastereoselective reduction of 2a-f with NaBH4 gave the threo-aminoalcohols (5a-f), which may be explained by the Felkin-Anh model. This was confirmed by converting 5a-f into trans-5-trifluoromethyl-2-oxazolidinones (6a-f) in good yields.
Kawase
M
M
Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan.
Hirabayashi
M
M
Kumakura
H
H
Saito
S
S
Yamamoto
K
K
D000089:Acetic Anhydrides; D000596:Amino Acids / Q000138:chemical synthesis* / Q000494:pharmacology; D001894:Borohydrides; D003500:Cyclization; D005463:Fluoroacetates; D007202:Indicators and Reagents; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry
D000089:Acetic Anhydrides; D000596:Amino Acids; D001894:Borohydrides; D005463:Fluoroacetates; D007202:Indicators and Reagents; D011725:Pyridines; C017958:trifluoroacetic anhydride