title: Bulky phosphinines: from a molecular design to an application in homogeneous catalysis.
abstract: The design and preparation of an asymmetrically substituted and bulky phosphinine was achieved by introducing sterically demanding substituents into specific positions of a rigid phosphorus-heterocyclic framework. Compound 5 shows, at the same time, axial chirality and a sufficiently high energy barrier for internal rotation to prevent enantiomerization. Both enantiomers of 5 were isolated by means of chiral analytical HPLC, and their absolute configurations could be assigned by combining experimental data and DFT calculations. Despite its substitution pattern, 5 can still coordinate to transition-metal centers through the lone pair of electrons on the phosphorus atom. Rapid C-H activation on the adjacent aryl substituent at the 2-position of the phosphorus heterocycle was achieved by using [{Cp*IrCl2}2] (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl) as a metal precursor. A racemic mixture of 5 was applied as a π-accepting low-coordinate phosphorus ligand in the Rh-catalyzed hydroformylation of trans-2-octene, which showed a clear preference for the formation of 2-methyloctanal.
authors.affiliation: Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600 MB Eindhoven, The Netherlands.
authors.forename: Jarno J M
authors.initials: JJ
authors.lastname: Weemers
authors.forename: Willem N P
authors.initials: WN
authors.lastname: van der Graaff
authors.forename: Evgeny A
authors.initials: EA
authors.lastname: Pidko
authors.forename: Martin
authors.initials: M
authors.lastname: Lutz
authors.forename: Christian
authors.initials: C
authors.lastname: Müller