Special Products: 3.3.1–3.3.6.5

Blaser, Hans‐Ulrich; Pugin, Benoı̂t; Spindler, Felix

doi:10.1002/9783527618231.ch3e

Cited by 10 publications

(3 citation statements)

References 542 publications

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“…Among various catalysts, complexes of transition metals and chiral ligands as chiral homogeneous (pre)catalysis represent a convenient methodology for the synthesis of chiral molecules . The asymmetric hydrogenation reaction utilizing cheap molecular hydrogen to reduce prochiral substrates is widely applied even on the industrial scale. , Ru and Rh complexes have been used as catalysts to obtain excellent results, and other transition metals such as Ir, Ti, and so on are also effective. − In the periodic table, Pd, Ru, and Rh are all elements in the fifth period and group VIII. The Pd catalyst system has been applied to promote a wide range of useful synthetic organic reactions .…”

Section: Introductionmentioning

confidence: 99%

Highly Enantioselective Pd-Catalyzed Asymmetric Hydrogenation of Activated Imines

2007

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Pd/bisphosphines complexes are highly effective catalysts for asymmetric hydrogenation of activated imines in trifluoroethanol. The asymmetric hydrogenation of N-diphenylphosphinyl ketimines 3 with Pd(CF3CO2)/(S)-SegPhos indicated 87-99% ee, and N-tosylimines 5 could gave 88-97% ee with Pd(CF3CO2)/(S)-SynPhos as a catalyst. Cyclic N-sulfonylimines 7 and 11 were hydrogenated to afford the useful chiral sultam derivatives in 79-93% ee, which are important organic synthetic intermediates and structural units of agricultural and pharmaceutical agents.

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Section: Introductionmentioning

confidence: 99%

Highly Enantioselective Pd-Catalyzed Asymmetric Hydrogenation of Activated Imines

2007

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“…Asymmetric hydrogenation of 1 to ( R )- 2 catalyzed by chiral metal complexes is a straightforward chemical procedure . The reaction with an ( R )-DM-SEGPHOS/( S )-DM-DAIPEN−Ru(II) catalyst afforded ( R )- 2 in 97% ee (substrate-to-catalyst molar ratio (S/C) = 1000, 30 atm H 2 , room temperature, 16 h, 97.5% conversion), , but the catalytic activity was not sufficient for practical use . Since 1995, we have reported that chiral RuCl 2 (diphosphine)(diamine) − and RuCl 2 (diphosphine)(pica) , (PICA = α-picolylamine) complexes act as excellent catalysts for asymmetric hydrogenation of ketones in base-containing alcoholic solvents.…”

Section: Introductionmentioning

confidence: 99%

Practical Asymmetric Hydrogenation of 3-Quinuclidinone Catalyzed by the XylSkewphos/PICA−Ruthenium(II) Complex

Tsutsumi

Katayama

Utsumi

et al. 2009

Org. Process Res. Dev.

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Asymmetric hydrogenation of 3-quinuclidinone with RuBr 2 [(S,S)xylskewphos](pica) in a base containing ethanol affords (R)-3-quinuclidinol in 88-90% ee (XylSkewphos ) 2,4-bis(di-3,5-xylylphosphino)pentane, PICA ) r-picolylamine). The optical purity of the product is readily increased to >99% by recrystallization. The hydrogenation of a 4.3-kg scale with a substrate-to-catalyst molar ratio of 100 000 under 15 atm of H 2 at 30-45 °C completes in 4 h. Use of methanol or 2-propanol as a solvent decreases the catalyst efficiency. RuCl 2 (skewphos)(pica), and RuCl 2 (tolbinap)(pica) which have similar structures, are less effective for this reaction.

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“…There is no doubt that homogeneous asymmetric hydrogenation plays an especially important role in asymmetric syntheses, providing an effective route to optically active compounds . A majority of these reactions are catalyzed by transition metal complexes such as Rh and Ru catalysts, some of which have been successfully applied to industrial production …”

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confidence: 99%