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The first enantioselective synthesis of chiral norbornane-type 1,4-diamine ligand

The asymmetric synthesis of trans-2,3-bis(aminomethyl)norbornane was performed starting with endo-2,3-norbornene dicarboxylate anhydride. Desymmetrization of meso-anhydride 1 and following selective epimerization gave the trans-monoester (+)-3 with a high enantiomeric excess (98% e.e.). LiAlH4 reduction of the trans-monoester to the 1,4-diol, which was then treated with phthalimide under Mitsunobu conditions and, following a Gabriel type amine synthesis with hydrazine hydrate, yielded a saturated and unsaturated diamine mixture. Hydrogenation of mixture finally afforded saturated diamine (+)-8 with a yield of 37%.