General Enantioselective C−H Activation with Efficiently Tunable Cyclopentadienyl Ligands

Abstract

Cyclopentadienyl (Cp) ligands enable efficient steering of various transition‐metal‐catalyzed transformations, in particular enantioselective C−H activation. Currently only few chiral Cp ligands are available. Therefore, a conceptually general approach to chiral Cp ligand discovery would be invaluable as it would enable the discovery of applicable Cp ligands and to efficiently and rapidly vary and tune their structures. Herein, we describe the three‐step gram‐scale synthesis of a structurally diverse and widely applicable chiral Cp ligand collection (JasCp ligands) with highly variable and adjustable structures. Their modular nature and their amenability to rapid structure variation enabled the efficient discovery of ligands for three enantioselective RhIII‐catalyzed C−H activation reactions, including one unprecedented transformation. This novel approach should enable the discovery of efficient chiral Cp ligands for various further enantioselective transformations.

Enantiodivergent Desymmetrization in the Rhodium(III)‐Catalyzed Annulation of Sulfoximines with Diazo Compounds

“…[2k,3] Theg roups of Cramer and Youh ave made significant contributions towards the development of Rh and Ir catalysts stabilized by C 2 -symmetric cyclopentadienyl ligands, [4] which enabled the enantioselective CÀHactivation of arenes and their functionalization with unsaturated coupling partners.W ard, Rovis,and Hyster took ad ifferent approach by using an achiral rhodium complex conjugated to ab iotin tag. [6] Very recently,P erekalin and co-workers applied ar eduction/nucleophilic addition approach to rhodium fulvene complexes to access planar-chiral Cp X Rh III catalysts. [6] Very recently,P erekalin and co-workers applied ar eduction/nucleophilic addition approach to rhodium fulvene complexes to access planar-chiral Cp X Rh III catalysts.…”

“…[5] Recently,A ntonchick, Waldmann, and co-workers developed an enantioselective cycloaddition of imino esters to fulvenes for the synthesis of chiral cyclopentadienyl ligands and the corresponding Rh III catalysts. [6] Very recently,P erekalin and co-workers applied ar eduction/nucleophilic addition approach to rhodium fulvene complexes to access planar-chiral Cp X Rh III catalysts. [7] In these asymmetric catalytic systems,t he stereodetermining process is the CÀHa ctivation (in desymmetrization), the migratory insertion process, [4a,b,8] or the reductive elimination.…”

Axially Chiral Dibenzazepinones by a Palladium(0)‐Catalyzed Atropo‐enantioselective C−H Arylation

“…[6,7] In contrast, effective control of atropo-enantioselectivity,whilst simultaneously forging the axis of chirality,appears inherently more challenging (Scheme 1b). [8][9][10] To date,o nly two substrates have been prepared under palladium catalysis by this approach (up to 72 % ee and 27 %yield). [8] Our group has along-standing interest in the development and application of chiral ligand families,p articularly for enantioselective C À Hf unctionalization.…”

Manganese(I)‐Catalyzed Regio‐ and Stereoselective 1,2‐Diheteroarylation of Allenes: Combination of C−H Activation and Smiles Rearrangement

“…[5,6] On the other hand, owing to their multifold chemical reactivities, [1] allenes have been utilized as intriguing coupling partners in CÀHa ctivation reactions. [7][8][9][10] Thet ypical reaction manifold was the direct hydroarylation of allenes,w hich gave the direct allylation or alkenylation reactions (Scheme 1a,p ath A). [7] Upon allene migratory insertion/b-hydrogen [7d, 8] or b-oxygen [9] elimination, the C À Hallenylation and dienylation was also accessible (Scheme 1a,path B).…”

“…[7][8][9][10] Thet ypical reaction manifold was the direct hydroarylation of allenes,w hich gave the direct allylation or alkenylation reactions (Scheme 1a,p ath A). [7] Upon allene migratory insertion/b-hydrogen [7d, 8] or b-oxygen [9] elimination, the C À Hallenylation and dienylation was also accessible (Scheme 1a,path B). TheC À Hannulation of allene was also known to effect the construction of intriguing heterocycles (Scheme 1a,p ath C).…”