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DENEB™ – New Achievements in the Asymmetric Transfer Hydrogenation

Recent developments in DENEB™ catalytic synthesis allows selective access to complex molecules from easily available starting compounds

Ruthenium based catalytic asymmetric transfer hydrogenation, has been proven to be an important technology for the manufacturing of pharmaceutical, fragrance and agricultural chemicals without using flammable hydrogen gas. However, large consumption of catalyst and limits on applicable substrates, have been known as a disadvantage to conventional technology. A good example is the production of optically pure alcohols using conventional technology based on the RuCl(arene)(N-sulfonylated diamine) catalyst, which is widely implemented by chemical industries.

The Takasago group made an important advancement in overcoming these significant limitations, by introducing new oxo-tethered Ru amido DENEB® complexes (Fig. 1).  This modification allowed for an outperformance of prior more conventional Ruthenium catalyst in use. (S,S)-Ts-DENEB® 44-0186 exhibited excellent catalytic performance for both asymmetric transfer hydrogenation as well as the traditional Hhydrogenation of ketonic substrates under neutral conditions without any co-catalysts to form chiral secondary alcohols with high levels of enantioselectivity [1]. DENEB® resulted in catalyst loading that could be reduced to 1/​60 the mass of comparable conventional catalysts.  This resulted in reducing catalyst costs, residual Ru impurities in products, as well attaining higher enantioselectivities over a wider substrate range.

Image1                    Image2

(R,R)-Ts-DENEB® 44-0185                               (S,S)-Ts-DENEB® 44-0186


Image3                           Image4

(R,R)-Ms-DENEB® 44-0255                                  (S,S)-Ms-DENEB® 44-0256

Figure 1.
DENEB® family of oxo-tethered Ru complexes that exhibit
excellent catalytic performance for asymmetric transfer hydrogenation

Furthermore, (S,S)-Ts-DENEB® 44-0186 plays an important role in the development of an efficient synthesis of optically active ceramide compound (D-erythro-CER[NDS]) via asymmetric transfer hydrogenation using a pipes-in-series flow reactor with oxo-tethered Ru complex catalyzing dynamic kinetic resolution [2]. In addition (R,R)-Ts-DENEB® 44-0185 , (S,S)-Ts-DENEB® 44-0186 and (R,R)-Ms-DENEB® 44-0255 all exhibit excellent catalytic performance in the dynamic kinetic resolution-asymmetric transfer hydrogenation (DKR-ATH) reactions for cyclic α-halogenated ketones [3] and racemic substituted ketones, enabling multiple stereocontrolled ring formations [4].

(S,S)-Ms-DENEB® 44-0256 is also a useful catalyst for the selective ATH of α-substituted acetophenones [5], affording an enantioselective and robust synthetic process to obtain a useful intermediate for making the β2-adrenergic receptor agonist, used in the pharmaceutical industry [6].

For information that is more detailed please review the corresponding technical notes.


  1.       J. Am. Chem. Soc. 2011, 133, 14960.
  2.       Org. Process Res. Dev. 2019, 23, 452.
  3.       Org. Lett. 2021, 23, 3070.
  4.       J. Am. Chem. Soc. 2019, 141, 16354.
  5.       Adv. Synth. Catal. 2018, 360, 568.
  6.       Org. Process Res. Dev. 2015, 19, 315.


Featured Products:

44-0185 N-[(1R,2R)-1,2-Diphenyl-2-(2-(4-methylbenzyloxy)ethylamino)-ethyl]-4-methylbenzene sulfonamide(chloro)ruthenium(II) (R,R)-Ts-DENEB® (1333981-84-2)

44-0186 N-[(1S,2S)-1,2-Diphenyl-2-(2-(4-methylbenzyloxy)ethylamino)-ethyl]-4-methylbenzene sulfonamide(chloro)ruthenium(II) (S,S)-Ts-DENEB® (1384974-37-1)

44-0255 Chloro{N-[(1R,2R)-2-[(S)-[2-[[1,2,3,4,5,6-?)-4-methylphenyl]methoxy]ethyl]amino]-1,2-diphenylethylmethanesulfonamidato}ruthenium(II) (R,R)-Ms-DENEB® (1333981-86-4)

44-0256 Chloro{N-[(1S,2S)-2-[(R)-[2-[[1,2,3,4,5,6-?)-4-methylphenyl]methoxy]ethyl]amino]-1,2-diphenylethylmethanesulfonamidato}ruthenium(II) (S,S)-Ms-DENEB® (1361318-83-3)


Related Products & Resources:

96-6955 Takasago ATH (Asymmetric Transfer Hydrogenation) Catalyst Kit
Catalysts & Chiral Catalysts
Catalysts & Ligands – Sold in Collaboration with Takasago



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