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Please login to access the full content or check if you have access via Variation 1: (Arene)tricarbonylchromium(0) Complexes as Chiral Ligands

DOI: 10.1055/sos-SD-002-00214

Kündig, E. P.; Pache, S. H.Science of Synthesis, (20032209.

Following the wide success of ferrocene-derived planar chiral ligands[‌228‌] and the rapid development of enantioselective and diastereoselective methodologies in the field of (arene)tricarbonylchromium(0) complexes (see Section 2.4.7), it was only a matter of time before attention was directed to chiral ligands based on this group.[‌199‌] A limitation in their application is noted in as far that the chromiumaryl bond is less robust that the FeCp bond. The general synthetic routes to nonracemic planar chiral ligands of this class of compounds have been those outlined in Section 2.4.7, with the first syntheses based on (S)-α-methylbenzylamine derivatives (see Scheme 39). Examples of nonracemic planar chiral mono- and bidentate ligands are shown in Scheme 57 and include complexes 63 (synthesis in Scheme 15),[‌156‌] 107 (R1=PPh2) (synthesis in Scheme 39),[‌229‌] 143 (prepared by enantioselective lithiation of the tricarbonylchromium(0) complex of triphenylphosphine oxide),[‌340‌] 144,[‌341‌] 145,[‌232‌] and 146.[‌342‌] Ligand 145 was synthesized by reacting ent108 (see Scheme 37) with lithium diphenylphosphide, and ligand 146 was obtained by enantioselective lithiationbromination of the carbamate complex 118 (Scheme 40), Suzuki coupling, and nucleophilic substitution. Complex 107 serves as a convenient starting material for the wide range of ligands listed under structure 144.[‌341‌,‌381‌,‌382‌]

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