palladium‐catalyzed asymmetric OHinsertionreaction was developed. Palladium complexes with chiral spiro bisoxazoline ligands promoted the insertion of α‐aryl‐α‐diazoacetates into the OH bond of phenols with high yield and excellent enantioselectivity under mild reaction conditions. This palladium‐catalyzed asymmetric OHinsertionreaction provided an efficient and highly enantioselective method for the preparation
Cinchona alkaloids are effective additives for enantioselective O–H insertion of α-phenyldiazoacetate and water by rhodium(II) complexes. Addition of silica gel promotes O–H insertion in the reaction rate and the reaction proceeds smoothly at less than the freezing point of water, e.g., −10 °C, and provided mandelate in up to 50% ee. The results reported here are the highest asymmetric inductions obtained to date for O–H insertions via a Rh-carbenoid.
into the O-H bond of phenols was developed. A homobinuclear silver complex with a chiral phosphorous ligand was created in situ from AgNTf2 and (S)-XylylBINAP (in a 2:1 mole ratio). Detailed mechanistic studies using combined experimental and computational techniques revealed that one silver atom center of the catalyst forms a silver carbene and another one works as a Lewis acid for the nucleophilic