title: Synthesis of quaternary carbon stereocenters by copper-catalyzed asymmetric allylic substitution of allyl phosphates with arylboronates.
abstract: A copper-catalyzed asymmetric allylic substitution of γ,γ-disubstituted allyl phosphates with arylboronates has been developed for the construction of quaternary stereocenters. High regio- and enantioselectivities have been achieved by employing a hydroxy-bearing chiral N-heterocyclic carbene ligand, and both E and Z substrates provide the same enantiomer as the major product. The mechanistic aspect of this catalysis has also been investigated to find that a 1:1 copper/ligand complex is most likely responsible for the present asymmetric catalysis, and the reaction proceeds with almost perfect 1,3-anti stereochemistry with respect to the allylic electrophile.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University , Sakyo, Kyoto 606-8502, Japan.
authors.forename: Momotaro
authors.initials: M
authors.lastname: Takeda
authors.forename: Keishi
authors.initials: K
authors.lastname: Takatsu
authors.forename: Ryo
authors.initials: R
authors.lastname: Shintani
authors.forename: Tamio
authors.initials: T
authors.lastname: Hayashi