Hydrogenation of cyclohexene by molecular hydrogen catalysed by linear polymers highly loaded with rhodium complexes

Naaktgeboren, A.J.; Nolte, Roeland J. M.; Drenth, W.

doi:10.1016/0304-5102(81)87022-8

Cited by 9 publications

(3 citation statements)

References 23 publications

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“…After 15 h the chloroform solution was washed four times with 5% aqueous Na2C03 and twice with H20 and dried over Na2S04. After evaporation of the solvent, 12 was obtained in quantitative yield: mp 47 °C; M+ m/e 273; [a]22D +19.3 (c 0.8, chloroform); NMR (CDC13) 7.35 (m, 10 H, aromatic ), 4.0 (J = 6.7 Hz, m, 1 H, HCC1), 3.55 and 3.74 (Jgem = 13.5 Hz, 2 d, 4 H, CH2Ph), 2.69 and 2.74 (J = 7.5 and 6.3 Hz, Jgem = 13.5 Hz, 2 H, CH2N), 1.40 (J = 6.6 Hz, d, 3 H, CH3); 13C NMR (CDC13) 138.94,128.78,128.12,126.97 (aromatic C), 61.89 (CH2N), 59.00 (CH2Ph), 55.34 (HCC1), 22.98 (CH3). Anal.…”

Section: Poly[(s)-(l-(acetoxymethyl)-2-methylpropyl)iminomethylene] (3c)mentioning

confidence: 99%

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Helical configuration of poly(iminomethylenes). Synthesis and CD spectra of polymers derived from optically active isocyanides

Beijnen¹,

Nolte²,

Naaktgeboren³

et al. 1983

Macromolecules

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Each of nine chiral isocyanides, R*-N=C, in enantiomerically pure or almost pure form, is polymerized to the corresponding poly(iminomethylene), [R*-N=C<]n. The group R* either contains at least one substituent (carboxylic ester, phenyl, phosphinyl) or is unsaturated (C=C, C=C). The polymers are of the rigid-rod type with a helical main chain of carbon atoms. Because of the chirality of R*-N=C either the P or the M helix is preferentially formed. CD spectra and optical rotation at 578 nm are determined and compared with those of the model compounds R*-N=CH(i-C4H9) and the monomers. This comparison and earlier calculations on [i-C4H9-N=C<]n allowed the assignment to each polymer of the excess screw sense. The screw sense is also theoretically predicted by two approaches, a thermodynamic and a kinetic one. The latter approach gives an appreciably better fit with the experimental results.

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Section: Poly[(s)-(l-(acetoxymethyl)-2-methylpropyl)iminomethylene] (3c)mentioning

confidence: 99%

“…These polymeric systems are of interest as chiral catalysts, e.g., in hydrogenation reactions. 12 Results and Discussion Synthesis. Polymers 3a-i were prepared according to the general procedure of Scheme I. Optically active Nformylamines served as starting materials.…”

Section: Introductionmentioning

confidence: 99%

Helical configuration of poly(iminomethylenes). Synthesis and CD spectra of polymers derived from optically active isocyanides

Beijnen¹,

Nolte²,

Naaktgeboren³

et al. 1983

Macromolecules

Self Cite

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show abstract

“…Thus when the relative rates of hydrogenation of I-hexene and cyclohexene in the presence of [Rh(PPh 3 h CI] supported on 1%, 2% and 4% cross-linked polystyrene are studied, the influence of solvent depends on substrate concentration [23,39]. Tetrahydrofuran meets both requirements and results in enhanced hydrogenation rates for the sterically more demanding cyclohexene than benzene [39,40] Although supported catalysts have advantages of selectivity with respect to substrate and ease of separation of the catalyst after reaction, as compared to homogeneous catalysts, most industrialists still tend to ask about the relative activities of the two types of catalysts. These complex observations arise from the mutually conflicting effects of an increase in substrate concentration within the resin beads when the polarity of the solvent is increased and the lower resin swelling power of ethanol than benzene.…”

Section: Nature Of the Solventmentioning

confidence: 99%