Synthesis of Dendritic Schiff Base Ligands for Titanium Catalyzed Enantioselective HDA Reaction of Danishelfsky's Diene with Aldehydes

A new type of dendritic NOBIN derived Schiff base ligands hasbeen synthesized and applied to titanium catalyzed hetero-Diels-Alder reaction of Danishelfsky’s diene and aldehydes, affordingthe corresponding 2-substituted 2, 3-dihydro-4H-pyran-4-one ingood yields and moderate enantioselectivities (up to 59.2%ee). It was found that the size of dendron attached to the tri-dentated ligands has slight impact on the enantioselectivity ofthe reaction and the second generation of dendritic ligand ex-hibited the best enantioselectivity.

<正> A new type of dendritic NOBIN derived Schiff base ligands hasbeen synthesized and applied to titanium catalyzed hetero-Diels-Alder reaction of Danishelfsky’s diene and aldehydes, affordingthe corresponding 2-substituted 2, 3-dihydro-4H-pyran-4-one ingood yields and moderate enantioselectivities (up to 59.2%ee). It was found that the size of dendron attached to the tri-dentated ligands has slight impact on the enantioselectivity ofthe reaction and the second generation of dendritic ligand ex-hibited the best enantioselectivity.