Process for producing optically active isopulegol and optically active menthol

摘要

It is an object of the present invention to provide an optically active isopulegol and a process for producing optically active menthol which are less waste contaminating the environment and can save manufacturing costs. An optically active citronellal is obtained by asymmetric isomerization of geraniol and / or nerol using a specific optically active ruthenium catalyst, and an optically active citronellal is obtained by using an aluminum catalyst in which an alkyl aluminum compound and a specific hydroxy compound are mixed, Optically active isopulegol can be obtained with high yield and high selectivity by carrying out a selective cyclization reaction.