Mechanistic and Synthetic Studies in Catalytic Allylic Alkylation with Palladium Complexes of 1-(2-Diphenylphosphino-1-naphthyl)isoquinoline

Article abstract of DOI:10.1016/S0040-4020(01)89381-9

The title complexes are highly reactive catalysts for the reaction between (E)-1,3-diphenyl-2-propenyl acetate and dimethyl malonate ion; the enantiomer excess varies between 67percent and 98percent depending on how the reaction is conducted, with the best result obtained in CH3CN at -13 deg C in the presence of 15-crown-5.With 2-cyclohexyl acetate the reaction was much slower and the best e.e. obtained was 67percent.With 1,1,3-triphenyl-2-propenyl acetate, reaction was again much slower than in the first case, the best e.e. was 47percent, and the configurational correlation between catalyst and reactant was in the opposite sense.Many of the trends can be satisfatorily rationalised by recourse to the NMR spectra of a series of Pd allyl complexes.In the case of the (E,E)-1,3-diphenylallyl complexe, two diastereomers were observed and their configurations assigned with the aid of nOe experiments.The results are best interpreted if the reaction proceeds through a late transition-state with nucleophilic attack on the allyl trans- to the phosphorous of the ligand and preferentially on the predominant diastereomer.