A Convenient Method for Preparation of α-Imino Carboxylic Acid Derivatives and Application to the Asymmetric Synthesis of Unnatural α-Amino Acid Derivative.
We describe herein a manganese(IV) oxide-mediated oxidation of N-p-methoxyphenyl (PMP)-protected glycine derivatives for the synthesis of α-imino carboxylic acid derivatives. Using this methodology, utilization of unstable glyoxic acid derivatives was avoided. Furthermore, using this methodology we synthesized novel α-imino carboxylic acid derivatives such as α-imino phenyl ester, perfluoroalkyl etsers, imides, and thioester. The asymmetric Mannich reaction of those novel imine derivatives with 1,3-dicarbonyl compound is also described, and the novel α-imino imide gave improved chemical yield and stereoselectivity compared with those obtained by the use of the conventional α-imino ester-type substrate.
['Inokuma|Tsubasa|T|', 'Jichu|Takahisa|T|', 'Nishida|Kodai|K|', 'Shigenaga|Akira|A|', 'Otaka|Akira|A|']
D000596:Amino Acids D066241:Carbon-13 Magnetic Resonance Spectroscopy D002264:Carboxylic Acids D007098:Imino Acids D066244:Proton Magnetic Resonance Spectroscopy D021241:Spectrometry, Mass, Electrospray Ionization
α-imino carboxylic acid derivative unnatural α-amino acid asymmetric organocatalysis heterogeneous oxidant thiourea