Palladium on carbon encapsulated in POEPOP1500: A resin-supported catalyst for hydrogenation reactions

Organic Letters

Volumn 4, Issue 1, 2002, Pages 27-30

  Jansson, Anita M ^a   Grøtli, Morten ^a,b   Halkes, Koen M ^a,c   Meldal, Morten ^a  

^a CARLSBERG LABORATORY   (Denmark)

^b UNIVERSITY OF OSLO   (Norway)

^c UTRECHT UNIVERSITY   (Netherlands)

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EID: 0013218151     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol016812x     Document Type: Article

References (21)

1. Reviews: (a) Shuttleworth, S. J.; Allin, S. M.; Sharma, P. K. Synthesis 1997, 1217.
2. (b) Shuttleworth, S. J.; Allin, S. M.; Wilson, R. D.; Nasturica, D. Synthesis 2000, 1035.
3. (c) Drewry, D. H.; Coe, D. M.; Poon, S. Med. Res. Rev. 1999, 19, 97.
4. (d) de Miguel, Y. R. J. Chem. Soc., Perkin Trans. 1 2000, 4213.
5. (e) Lindner, E.; Schneller, T.; Auer, F.; Mayer, H. A. Angew. Chem., Int. Ed. 1999, 38, 2154.
6. (f) Pittman, C. U., Jr. Polym. News 1998, 23, 416.
7. (g) Choplin, A.; Quignard, F. Coord. Chem. Rev. 1998, 178-180, 1679.
8. (a) Jo, Y.-D.; Ahn, J.-H.; Ihm, S.-K. Polym. Int. 1997, 44, 49.
9. (b) Zecca M.; Fišera, R.; Palma, G.; Lora, S.; Hronec, M.; Králik, M. Chem. Eur. J. 2000, 6, 1980.
10. (c) Niu, Y.; Yeung, L. K.; Crooks, R. M. J. Am. Chem. Soc. 2001, 123, 6840.
11. (a) Renil, M.; Meldal M. Tetrahedron Lett. 1996, 37, 6185.
12. (b) Grøtli, M.; Gotfredsen, C. H.; Rademann, J.; Buchardt, J.; Clark, A. J.; Duus, J. Ø; Meldal, M. J. Comb. Chem. 2000, 2, 108.
13. (c) Grøtli, M.; Rademann, J.; Groth, T.; Lubell, W. D.; Miranda, L. P.; Meldal. M. J. Comb. Chem. 2001, 3, 28.
14. 2 and subsequent measurement of the UV absorbency of the adduct of dibenzofulvene and piperidine formed on treatment of a weighed polymer sample with 20% piperidine in DMF. Loading: 0.25 mmol/g. Swelling was determined by the syringe technique, described in ref 5 (Figure 1).
15. Auzanneau, F.-I.; Meldal, M.; Bock, K. J. Pept. Sci. 1995, 1, 31.
16. General Procedure for Hydrogenation Reactions. The substrate (5 μmol) was dissolved in the appropriate solvent (acetonitrile, entry A and B, or methanol/water 10:1, entry C, 0.4 mL), and the solution was added to the resin-Pd/C (6 mg, 500 < x < 1000 μm) in a Teflon tube. After 30 min of swelling, the Teflon tubes were placed in a Parr apparatus and after flushing with argon and hydrogen, hydrogenation was started under pressure (40 or 20 bar) or under atmospheric pressure in room temperature, overnight, without stirring. The resin was filtered off and washed with acetonitrile (entries A and B) or 50% aqueous methanol (entry C), 2 × 0.2 mL. The combined solutions were analyzed with HPLC and ES-MS (entry A).
17. 2O 9:1); linear gradient from 100% A to 100% B in 25 min; flow rate 1 mL/min; wavelength 215 nm. Retention times: entry A, 23.7 min (1), 24.5 min (2); entry B, 10.5 min (3), 12.6 min (4); entry C, 16.6 min (5), 10, 2 min (6).
18. Electrospray spectra were aquired in positive mode on a VG Quattro triple quadropole mass spectrometer (Micromass, Ldt.).
19. 4)
20. Palladium analysis of filtered hydrogenation solutions was performed by FI-ICP-MS (flow-injection inductively coupled plasma-MS, ELAN-5000, PE Sciex) with Rh as internal standard (detection limit 0.05 μg Pd /L). Sample preparation: After each cycle of hydrogenation (with substrate 3) half of the volume (0.4 mL), after filtration and washing (ref 6), was concentrated, and the residue was dissolved in 1 M HCl (10 mL) for Pd analysis. The Pd content in samples from cycle 1-5 was measured to be 12, 8, 3, 3, and 3 μg Pd /L, respectively. This corresponds to an average loss of 0.1% Pd per hydrogenation cycle. (Pd content of blank solution with no catalyst added was 0.07 μg Pd /L; all samples were analyzed three times, with RSD < 3%.)
21. Palladium on activated carbon (10% Pd) was purchased from Aldrich.