Resolution and asymmetric synthesis of ortho-substituted (benzaldehyde)tricarbonylchromium complexes

Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C2‐Symmetrical 1,2‐Diamine as Auxiliary

“…The reaction of (benzaldehyde)tricarbonylchromium with ( R , R )‐2,2′‐bipyrrolidine ( 1 ) was performed as described for other aminals,6h,10 the only difference being the addition of molecular sieves to ensure drier conditions and protection from sunlight due to the sensitivity of this complex. Aminal 2 (Scheme ) could be obtained in 88 % yield after recrystallisation from diethyl ether.…”

“…The absolute configuration and ee of 3a were determined after hydrolysis to aldehyde 4a . Comparison of its optical rotation with literature data was performed after formation of aminal 6 with ( R , R )‐ N , N ′ ‐dimethylcyclohexane‐1,2‐diamine ( 5 ; Scheme ) 6h…”

Lithiation/Electrophilic Quench of [(η5‐Cyclohexadienyl)Mn(CO)3]: Versatile Functionalization and Resolution of Planar Chirality in the Organomanganese Series

“…More recently, Chung and co‐workers developed an approach specifically devoted to enantioenriched acetoxy‐substituted η 5 ‐cyclohexadienyl complexes by the addition of nucleophiles to [(η 5 ‐oxocyclohexadienyl)Mn(CO) 3 ] in the presence of chiral ligands 15. Some time ago, we described the resolution of ortho ‐substituted (η 6 ‐benzaldehyde)tricarbonylchromium complexes with chiral diamines with a C 2 symmetry axis 16. Thus, we decided to test the potential of such a chiral diamine for the resolution of a racemic mixture of [(η 5 ‐formylcyclohexadienyl)Mn(CO) 3 ] ( 14 ).…”

Kinetic Resolution of Planar‐Chiral (η6‐Arene)Chromium Complexes by Molybdenum‐Catalyzed Asymmetric Ring‐Closing Metathesis

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Planar-chiral (h 6 -arene)chromium complexes are useful chiral scaffolds in asymmetric synthesis, and have found widespread application as chiral ligands for asymmetric catalysis, or as chiral building blocks for natural product syntheses. [1] Typical methods for the preparation of enantiomerically enriched planar-chiral (arene)chromium species are based either on the optical resolution of racemates [2] or on stereoselective transformations, which include diastereoselective complexation, [3] diastereo-or enantioselective ortho-lithiation by utilizing a chiral directing group or a chiral base, [4] and diastereo-or enantioselective nucleophilic addition/hydride abstraction. [5] Whereas these methods require a stoichiometric amount of chiral reagents or auxiliaries, asymmetric catalysis is an attractive and effective alternative for preparing optically active (h 6 -arene)chromium complexes.

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