Asymmetric Hydrogenation of (<i>Z</i>)‐α‐(Acetylamino)‐cinnamic Acid by a Rh/norphos Catalyst

Brunner, Henri; Pieronczyk, W.

doi:10.1002/anie.197906201

Cited by 84 publications

(12 citation statements)

References 8 publications

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“…The hydrogenations of (Z)-l (R1 = aryl) are, conversely, more rapid and more highly enantioselective than hydrogenations of the corresponding E isomers under comparable conditions. When phosphines [23][24][25][26][27] are used, the (Z)-l (R1 = alkyl) isomers are hydrogenated more enantioselectively and, with the exception of (Z)-10, more slowly than the E isomers. To the best of our knowledge, comparative hydrogenations of (Z)-and (E)-l (R1 = aryl) with these phosphines have not yet been reported.…”

Section: Discussionmentioning

confidence: 99%

Catalytic asymmetric hydrogenation of methyl (E)- and (Z)-2-acetamido-3-alkylacrylates

Scott¹,

Keith²,

Nix³

et al. 1981

J. Org. Chem.

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Rhodium-chiral phosphine complex catalyzed homogeneous hydrogenations of methyl (Z)-and (E)-2-acetamido-4-methoxybut-2-enoates ((ZJS)-10), methyl (Z)-and (E)-2-acetamidohex-2-enoates (,{ ß)-16A) and methyl (Z)-and (E)-2-acetamido-4-methylpent-2-enoates ((ZJE)-16B) are reported. With phosphines in which two achiral phosphorus atoms are connected by a chiral four-carbon unit, higher product enantiomeric excesses (ee's) are obtained from E than from Z substrates. With phosphines in which a two-carbon chiral unit separates two achiral phosphorus atoms, Z substrates are preferred. With dipamp (28), both Z and E substrates (particularly (ZJ5)-16A) are reduced with high enantioselectivity. The additional oxygen atom in substrates (Z,£)-10 has little effect on product ee with most phosphines.

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Section: Discussionmentioning

confidence: 99%

Catalytic asymmetric hydrogenation of methyl (E)- and (Z)-2-acetamido-3-alkylacrylates

Scott¹,

Keith²,

Nix³

et al. 1981

J. Org. Chem.

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“…5-Norbornen-2-yl-methanol and 1,5-dibromopentane were obtained from Aldrich Chemical Co. and used as received. ROMP initiators Mo(CHCMe 2 Ph)(NAr)(O- t -Bu) 2 (Ar = 2,6-C 6 H 3 - i -Pr 2 ; Ar‘ = 2,6-C 6 H 3 -Me 2 ), racemic NORPHOS (NORPHOS = 2- exo -3- endo -bis(diphenylphosphino)bicyclo[2.2.1]heptene), and P(NEt 2 )(oct) 2 were synthesized according to literature procedures. The synthesis of 2-(chloromethyl)-5-norbornene was carried out as described in the literature, except at room temperature instead of reflux temperature.…”

Section: Methodsmentioning

confidence: 99%

Fabrication of Quantum Dot/Polymer Composites: Phosphine-Functionalized Block Copolymers as Passivating Hosts for Cadmium Selenide Nanoclusters

et al. 1997

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Nearly monodisperse CdSe nanoclusters, surface-passivated with a layer of trioctylphosphine and trioctylphosphine oxide, have been sequestered within phosphine-containing domains in a diblock copolymer. A convergent approach to fabrication of these composites was adopted via independent synthesis of nanoclusters and polymer. Diblock copolymers of phosphine- or phosphine oxide-functionalized monomers and methyltetracyclododecene (MTD) were prepared by ring opening metathesis polymerization using Mo alkylidene initiators. Nanoclusters were prepared by pyrolysis of CdMe2 and SeP(octyl)3 in the presence of P(octyl)3 and OP(octyl)3. An immediate and sustained increase in electronic passivation is found for nanoclusters incorporated into octylphosphine-containing polymers. In contrast, nanoclusters in pure hydrocarbon or phosphine oxide-containing polymers rapidly lose passivation. Films of nanoclusters in a phosphine-containing polymer matrix were static cast from dilute solution. Under suitable conditions, the copolymers underwent microphase separation, and the metal chalcogenide clusters were predominantly sequestered within the phosphine-containing microdomains. The original, highly uniform cluster size distribution was unaffected.

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“…The resolution of thiol phosphine 4878 went through the diastereomeric dipalladium complexes of type 49 in which, after separation, the external Pd was displaced with ethylene diamine and the freed thiolato-S atom was alkylated with benzyl bromide. After subsequent liberation the resulting S-benzyl phosphine was treated with Na/NH3 phine (51). Interestingly, the phosphine 48 bearing free thiol group in the /3 position was found to be photochemically unstable and rearranged on exposure to light into optically pure ethylmethylphenylphosphine sulfide (52) with complete retention of configuration.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Scalemic P-Chiral Phosphines and Their Derivatives

Pietrusiewicz¹,

Zabłocka²

1994

Chem. Rev.

632

276

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Asymmetric Hydrogenation of (Z)‐α‐(Acetylamino)‐cinnamic Acid by a Rh/norphos Catalyst

Cited by 84 publications

References 8 publications

Catalytic asymmetric hydrogenation of methyl (E)- and (Z)-2-acetamido-3-alkylacrylates

Catalytic asymmetric hydrogenation of methyl (E)- and (Z)-2-acetamido-3-alkylacrylates

Fabrication of Quantum Dot/Polymer Composites: Phosphine-Functionalized Block Copolymers as Passivating Hosts for Cadmium Selenide Nanoclusters

Preparation of Scalemic P-Chiral Phosphines and Their Derivatives

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