Suzuki Cross-Coupling for Post-Complexation Derivatization of Non-Racemic Bis-Cyclometalated Iridium(III) Complexes

5 years ago

Suzuki Cross-Coupling for Post-Complexation Derivatization of Non-Racemic Bis-Cyclometalated Iridium(III) Complexes

Thomas Cruchter, Erik Winterling, Eric Meggers, Klaus Harms, Matthias Tripp, Thomas Mietke

A straightforward method for post-complexation derivatizations of diastereo- and enantiomerically pure bis-cyclometalated benzoxazole and benzothiazole iridium(III) complexes is reported. Triflate- and bromine-functionalized iridium(III) complex dimers, represented as [Ir(μ-Cl)(C^N)2]2, were converted to the corresponding diastereomeric complexes, represented as Ir(C^N)2(N^O), using readily available chiral salicyloxazolines and salicylthiazolines as ancillary ligands, which are represented as N^O. The Ir(C^N)2(N^O) complexes, formed as mixtures of diastereomers, were then resolved by flash chromatography and the diastereomerically pure complexes Ir(C^N)2(N^O) subjected to Suzuki cross-couplings. The post-complexation cross-couplings proceed without affecting the metal-located stereocenter and hence provide post-complexation derivatized non-racemic iridium(III) complexes, which were not easily accessible with previous methods. This strategy expands the toolbox to access functionalized non-racemic iridium(III) complexes for diverse applications in the life sciences, materials sciences, and catalysis. Last-minute changes: Suzuki cross- couplings within the ligand sphere of stereochemically defined triflate and bromide bearing iridium complexes expand the toolbox of functionalized non-racemic bis-cyclometalated iridium(III) complexes, useful for diverse applications in the life sciences, materials science, and asymmetric catalysis.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201701758