Enantioselective Hydrogenation of Aromatic Ketones Catalyzed by Ru Complexes of Goodwin−Lions-type sp²N/sp³N Hybrid Ligands R-BINAN-R‘-Py

Abstract

Goodwin-Lions-type sp2N/sp3N hybrid ligands R-BINAN-R'-Py possessing a C2 axis binaphthyl skeleton have been designed and synthesized. Combination of the new non-phosphine ligand with Ru(pi-CH2C(CH3)CH2)2(cod) has been revealed to catalyze the hydrogenation of aromatic ketones with high enantioselectivity of up to 99% ee. The reaction proceeds essentially without the need for any bases, but the reactivity is enhanced by the addition of KOt-C4H9 attaining an S/C ratio of up to 10 000. The success should expand the range of possibilities in designing catalysts not only for hydrogenation but also for many other reactions.

Asymmetric Hydrogenation and Transfer Hydrogenation of Ketones

“…However, the efficiency of the -allyl Ru precursor in combination with the phosphorous-free pyridylcontaining ligand L1 did not exceed that of the original [BINAP-Ru-diamine] complexes (Fig. 4) (Huang et al, 2006). Interestingly, this new catalyst system catalyzes the hydrogenation of 1-indanone only in the absence of a base.…”

Application of Proline‐Functionalised 1,2‐Diphenylethane‐1,2‐diamine (DPEN) in Asymmetric Transfer Hydrogenation of Ketones

“…The organic layer was filtered through a plug of silica and the solvent removed under reduced pressure to leave the product which was purified by column chromatography if necessary. Characterisation data and ee determination methods for reduction products [43][44][45][46][47][48][49][50] are given in the Supporting Information.…”

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

“…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.…”

“…A number of amine-containing isolated complexes for ketone hydrogenation have been reported. [5][6][7][8][9][10] The pentamethylcyclopentadienyl rhodium (III) and iridium (III) catalysts 4a and 4b respectively, derived from TsDPEN 3 have given excellent results. 5 A closely related Ru(II)/arene complex 5 has also been reported to be highly effective.…”

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