Synthesis of a Novel C 2 ‐Symmetric Bis‐oxazoline (=Bis[4,5‐dihydrooxazole]) and Its Application as Chiral Ligand in Asymmetric Transition Metal Catalysis

The new C 2 ‐symmetric bis‐oxazoline (=bis[4,5‐dihydrooxazole]) 2 with a chiral trans ‐(2 R ,3 R )‐2,3‐bis(3,5‐diphenylphenyl)cyclopropylidene (= trans ‐(2 R ,3 R )‐2,3‐bis([1,1′: 3′,1″‐terphenyl]‐5′‐yl)cyclopropylidene) backbone was efficiently synthesized ( Scheme ). All synthetic steps were easy to perform and led to the desired product in good overall yields. Compound 2 was tested and compared as ligand in several enantioselective catalytic reactions such as palladium(0)‐catalyzed enantioselective allylic alkylations and copper(I)‐catalyzed enantioselective cyclopropanations and aziridinations.