In connection with the synthesis of serratinine (A), the selective cyclization reaction of the 1, 2-cyclohexanediacetaldehyde derivatives, IIIa and IITb, through the intramolecular aldol condensation reaction was investigated. Cyclization reaction of IIIa or IITb by basic alumina or by the enamine method2) using piperidine acetate in dry benzene gave selectively IVa or IVb. On the other hand, cyclization reaction of IIIa or IIIb using excess pyrrolidine acetate in abs. MeOH afforded selectively Va or Vb which is suitable for the present purpose.