Chiral nitrogen-metal complexes for the asymmetric reduction of ketones

Preparation and Catalytic Performances of a Molecularly Imprinted Ru‐Complex Catalyst with an NH2 Binding Site on a SiO2 Surface

“…Synthesis of (1R,2R)-N-p-styrenesulfonyl-1,2-diphenyl-ethylenediamine (A): [99] (1R,2R)-1,2-Diphenylethylenediamine (1.0 g, 4.7 mmol) was dissolved in a mixture of CH 2 Cl 2 (15 mL) and Et 3 N (5 mL). A solution of p-styrenesulfonyl chloride (0.95 g, 4.7 mmol) in CH 2 Cl 2 (10 mL) was added at 273 K, and the mixture was stirred overnight at 293 K. It was then washed with 5 % aqueous NaOH solution (18 mL) and dried with MgSO 4 , and the solvent was evaporated under vacuum.…”

Enantioselective Synthesis of Alcohols and Amines by Iridium‐Catalyzed Hydrogenation, Transfer Hydrogenation, and Related Processes

“…after one day at room temperature (Scheme 52). [117] The analogous heterogenized version, in which (1S,2S)-N-(styrene-p-sulfonyl)-1,2-diphenylethylenediamine ((S,S)-99) was incorporated in a polymeric matrix, afforded similar enantioselectivity (94 % ee), but the reactions were slower (96 % conv. after three days) and recycling was unsuccessful.…”

Ir(III) complexes of diamine ligands for asymmetric ketone hydrogenation

“…2-Methylacetophenone was selected for study because it had given particularly promising results in preliminary results, and because orthosubstituted substrates can be challenging substrates to reduce in high ee. Of the ligands tested, the best results were obtained using those with relatively unhindered aromatic rings containing electron withdrawing groups (entries 3,4,6,12,13,15). With the exception of ligand 9l, diamines containing substituents at the ortho-position(s) gave lower asymmetric inductions (entries 7-9), and those with two ortho-substituents were particularly poor, possibly for steric reasons.…”

“…Relatively few organometallic complexes derived from amine ligands have been reported to be effective at the control of asymmetric hydrogenation reactions, [1][2][3][4][5][6][7][8][9][10] particularly in comparison to the large numbers of diphosphine 11,12 and mixed amine/phosphine 13,14 ligands which have been reported.…”

“…entries 2,3,5,6,8,10,14). In the case of tetralone 10g and 2,5-dimethoxyacetophenone 10d, ligand 9o was somewhat inferior.…”