The diastereoselective double Mannic reaction predominantly formed the tricyclic diamine 13 in 60% yield with the cyclohexyl group at endo-position to the bridge which has the identical configuration to our desired chiral diamine (-)-1. Reduction of keto-diamine 13 under Wolff-Kishner reaction conditions followed by hydrogenation reaction provide the final chiral diamine in 67% and 88% yields respectively.