10.1021/om030055k.s002
Ian Westmoreland
Ian
Westmoreland
Ian J. Munslow
Ian J.
Munslow
Paul N. O'Shaughness
Paul N.
O'Shaughness
Peter Scott
Peter
Scott
Chiral Titanium Bis(aminopyridinates) Based on a
Biaryl Backbone
American Chemical Society
2003
KH
C 2
Ph
Biaryl Backbone
reactive coordination sphere
biaryl backbone
reaction chemistry
cis structure
H 2 L
TiCl 3
SiMe 3 Cl
L TiMe 2
L TiCl 2
nonchelate aminopyridinate ligands
ligand system
dimethyl compound
2003-06-12 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Chiral_Titanium_Bis_aminopyridinates_Based_on_a_Biaryl_Backbone/3775329
The new chiral biaryl-bridged aminopyridine proligand H<sub>2</sub><b>L</b> is synthesized readily via
palladium-catalyzed amination. This ligand system provides a very robust environment for
reaction chemistry in comparison to known nonchelate aminopyridinate ligands. Reaction
with Ti(NMe<sub>2</sub>)<sub>4</sub> gives the <i>C</i><sub>2</sub>-symmetric amide [<b>L</b>Ti(NMe<sub>2</sub>)<sub>2</sub>] (91% isolated), which on reaction
with SiMe<sub>3</sub>Cl gives the chloride [<b>L</b>TiCl<sub>2</sub>] (95%). Metalation of H<sub>2</sub><b>L</b> with KH followed by
reaction with TiCl<sub>3</sub> and oxidation also gives [<b>L</b>TiCl<sub>2</sub>] (87%). This latter complex has been
crystallographically characterized and has the expected cis structure, in which the chirality
arising in the biaryl backbone is very well expressed in the reactive coordination sphere of
the metal. Reaction of [<b>L</b>TiCl<sub>2</sub>] with MeMgBr gives the dimethyl compound [<b>L</b>TiMe<sub>2</sub>] (72%).
The dibenzyl complex [<b>L</b>Ti(CH<sub>2</sub>Ph)<sub>2</sub>] is prepared directly from the reaction of H<sub>2</sub><b>L</b> with
[Ti(CH<sub>2</sub>Ph)<sub>4</sub>] (90%).