The synthesis of new C2-Symmetric chiral 1,4-diamino motif and application in catalytic asymmetric alkynylation of meso-epoxides

The efficient asymmetric preparation of the C 2 -symmetric chiral 1,4-diamine, (1R,25,4R,5S)-1,4-diamino-2,5-dimethylcyclohexane (5), and its salen ligands is described. With the Mitsunobu reaction as the key step, the overall yield of the four-step synthesis of 5 is 45%. The enantioselective alkynylation of meso-epoxides catalyzed by chiral gallium complexes is also achieved.