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Bulky Phosphinines: From a Molecular Design to an Application in Homogeneous Catalysis
Author(s) -
Weemers Jarno J. M.,
van der Graaff Willem N. P.,
Pidko Evgeny A.,
Lutz Martin,
Müller Christian
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201300557
Subject(s) - hydroformylation , steric effects , substituent , chemistry , chirality (physics) , enantiomer , aryl , lone pair , catalysis , ligand (biochemistry) , rhodium , transition metal , stereochemistry , crystallography , computational chemistry , organic chemistry , molecule , physics , biochemistry , nambu–jona lasinio model , chiral symmetry breaking , alkyl , receptor , quantum mechanics , quark
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 CH activation on the adjacent aryl substituent at the 2‐position of the phosphorus heterocycle was achieved by using [{Cp*IrCl 2 } 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.