Ligand Tuning in Asymmetric Catalysis: Mono- and Bis-Phospholanes for a Prototypical Pd-Catalyzed Asymmetric Allylation Reaction

摘要

Enantioselectivities and yields comparable to the best catalysts reported previously can be achieved in the addition of potassium dimethyl malonate to diphenylallyl acetate by the use of Pd(0) complexes of bis-phospholanes prepared from D-mannitol. By appropriate changes in the C_2-C_5 substituents, rare example of a useful monophosphine can also be prepared by a similar route. In both instances chirality of C_3 and C_5 oxygen seems to play a crucial role in the asymmetric induction.