CATALYTIC ASYMMETRIC INTRAMOLECULAR ALLYLATION OF ALDEHYDE

摘要

The intramolecular asymmetric allylation of aldehydes was catalyzed by a combination of pyrrolidine derivatives and Pd(0)to give 5-exo-cyclized aldehyde with fair ee in good yield.Chiral amidomonophosphanes,for example 1,have been one of our targets to visualize their ligand applicability in catalytic asymmetric carbon-carbon bond forming reactions.Their characteristics are there in phosphorous and amide carbonyl moieties as soft and hard coordinating sites for soft and hard metals.It was a logical extension to investigate the utility of the parent diphenylphosphinylmethyl-pyrrolidine(2)in chiral pyrrolidine-mediated asymmetric reaction of aldehydes.The pioneering work has been done by Hiroi,where the intermolecular asymmetric allylation of enamine preformed from beta-keto esters and 2 was catalyzed by palladium giving allylated quaternary carbon with high ee.We set our goal in the development of catalytic asymmetric intramolecular allylation of aldehydes by using catalytic or substoichiometric amount of chiral pyrrolidine derivatives.We describe herein the catalytic asymmetric intramolecular allylation of aldehydes with use of L-proline beta)and(S)-2-((diphenyl-phosphino)mefhyl)pyrrolidine(2).