Process for preparation of tetrasubstituted 5-azaspiro[2.4]- heptane derivatives and optically active intermediates thereof

A method for producing a compound represented by formula (VII):

• wherein R represents an aryl group which may have a substituent, an aralkyl group which may have a substituent, a C1 to C6 alkyl group which may have a substituent, or a chiral auxiliary which can form an ester bond with carboxylic acid;
• and R1 represents an aralkyl group which may have a substituent, which comprises:
• reacting a compound represented by formula (I):
• wherein R and R1 have the same meanings as defined above, with a methylating reagent in the presence of a base to produce a compound represented by formula (II):
• wherein R1 and R have the same meanings as defined above;
• reacting the compound represented by formula (II) with a compound represented by formula (III):
• wherein R′ represents a protective group for hydroxy group, and X represents a halogen atom or a leaving group employed in nucleophilic substitution, in the presence of a base to produce a compound represented by formula (IV):
• wherein R1, R, and R′ have the same meanings as defined above;
• removing the protective group for hydroxy group from the compound represented by formula (IV) to produce a compound represented by formula (V):
• wherein R1 and R have the same meanings as defined above;
• transforming the hydroxy group of the compound represented by formula (V) to a halogen atom or a leaving group employed in nucleophilic substitution to form a compound represented by formula (VI):
• wherein Y represents a halogen atom or a leaving group employed in nucleophilic substitution, and R1 and R have the same meanings as defined above;
• and
• treating the compound represented by formula (VI) under basic conditions.