A process for obtaining a compound (1) and an intermediate thereof in high yield and high optical yield is provided. A process for producing a compound (4), the process including reacting a compound (2) with a compound (3) in the presence of a base； and a process for producing a compound (1), the process including reacting a compound (2) with a compound (3) in the presence of a base to yield a compound (4) and then deesterifying the compound (4). wherein R represents an alkyl group having 1 to 6 carbon atoms or an aralkyl group having 7 to 8 carbon atoms.
