Process for preparing optically active amino acid derivatives

A process for producing an optically active amino acid derivative represented by the following formula (6):

• wherein R3 represents an optionally substituted cyclic or noncyclic alkyl group having 1 to 30 carbon atoms, an optionally substituted aralkyl group having 7 to 30 carbon atoms, an optionally substituted aryl group having 6 to 30 carbon atoms, an optionally substituted alkenyl group having 2 to 30 carbon atoms, or an optionally substituted alkynyl group having 2 to 30 carbon atoms, P2 represents a benzenesulfonyl group substituted by nitro at the 2- and/or 4-positions or hydrogen atom and * represents the position of an asymmetric carbon atom;
• or its salt characterized by comprising treating an optically active N-protected aziridine-2-carboxylic acid represented by the following formula (3):
• wherein P1 represents a benzenesulfonyl group substituted by nitro at the 2- and/or 4- positions and * is as defined above,
• or its salt with an organic metal reagent represented by the following formula (5):
• R3M (5)
• wherein R3 is as defined above and M represents an atomic group containing an alkali metal atom or an alkaline earth metal atom or an atomic group containing a zinc ion;
• followed by, if needed, deblocking.