title: Palladium catalyzed asymmetric hydrophosphination of α,β- and α,β,γ,δ-unsaturated malonate esters - efficient control of reactivity, stereo- and regio-selectivity.
abstract: Both PC-cyclometalated and PCP-pincer type palladium catalysts have recently been found to be robust and efficacious catalysts for the asymmetric P-H addition reaction involving activated olefins. Our studies on the asymmetric P-H addition of diphenylphosphine to malonate ester and α,β,γ,δ-alkylidenemalonate ester revealed for the first time that the catalyst choice can have a dramatic impact in terms of reactivity as well as regio- and stereo-control for this asymmetric hydrofunctionalization reaction. Besides showing significantly contrasting reactivity and stereoselectivity in the hydrophosphination reaction involving malonate ester, in the case of α,β,γ,δ-alkylidenemalonate ester, a novel regiodivergent method was developed with the 1,4-adduct being obtained exclusively with the PC-catalyst while the pincer catalyst produced only the 1,6-adduct.
authors.affiliation: Division of Chemistry & Biological Chemistry, School of Physical and Mathematical Sciences Nanyang Technological University, Singapore 637616. sumod@ntu.edu.sg pakhing@ntu.edu.sg.
authors.forename: Xiang-Yuan
authors.initials: XY
authors.lastname: Yang
authors.forename: Jun Hao
authors.initials: JH
authors.lastname: Gan
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Li
authors.forename: Sumod A
authors.initials: SA
authors.lastname: Pullarkat
authors.forename: Pak-Hing
authors.initials: PH
authors.lastname: Leung