A rapid and simple cleanup procedure for metathesis reactions

Organic Letters

Volumn 9, Issue 7, 2007, Pages 1203-1206

  Galan, Brandon R ^a   Kalbarczyk, Kyle P ^a   Szczepankiewicz, Steven ^a,b   Keister, Jerome B ^a   Diver, Steven T ^a  

^a UNIVERSITY AT BUFFALO   (United States)

^b CANISIUS COLLEGE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 34147157753     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0631399     Document Type: Article

References (25)

1. Grubbs, R. H., Ed. Handbook of Metathesis; Wiley-VCH: Weinheim, Germany, 2003; Vols. 1-3.
2. (a) Nguyen, S. T.; Johnson, L. K.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1992, 114, 3974-3975. Complex 1:
3. (b) Schwab, P.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1996, 118, 100-110. Complex 2:
4. (c) Scholl, M.; Ding, S.; Lee, C. W.; Grubbs, R. H. Org. Lett. 1999, 1, 953-956.
5. (d) Trnka, T. M.; Morgan, J. P.; Sanford, M. S.; Wilhelm, T. E.; Scholl, M.; Choi, T.-L.; Ding, S.; Day, M. W.; Grubbs, R. H. J. Am. Chem. Soc. 2003, 125, 2546-2558.
6. (a) Maynard, H. D.; Grubbs, R. H. Tetrahedron Lett. 1999, 40, 4137-4140.
7. (b) Grubbs, R. H. Org. React. 2004, 22, 123-1234.
8. (c) Ahn, Y. M.; Yang, K.; Georg, G. I. Org. Lett. 2001, 3, 1411-1414.
9. (d) Paquette, L. A.; Schloss, J. D.; Efremov, I.; Fabris, F.; Gallou, F.; Mendez-Andino, J.; Yang, J. Org. Lett. 2000, 2, 1259-1261.
10. (e) McEleney, K.; Allen, D. P.; Holliday, A. E.; Crudden, C. M. Org. Lett. 2006, 8, 2663-2666. Summary of methods:
11. (f) Conrad, J. C.; Fogg, D. E. Curr. Org. Chem. 2006, 10, 185-202.
12. For fast enyne metathesis, a rapid and irreversible quench is desirable. Kinetic studies in enyne metathesis led us to develop the technique described in this paper.
13. If a small amount of active catalyst remains during solvent evaporation or during crude sample storage, the product can undergo carbene-promoted polymerization (e.g., for a RCM, the reverse reaction: ROMP).
14. Galan, B.; Gembicky, M.; Dominiak, P. M.; Keister, J. B; Diver, S. T. J. Am. Chem. Soc. 2005, 127, 15702-15703.
15. Obrecht, R.; Hermann, R.; Ugi, I. Synthesis 1985, 400-402.
16. We typically run the metatheses and the treatment procedure in the fume hood. Because of its excellent ligand properties, the isocyanide 6 is assumed to be toxic. Due care should be used in handling the solid to avoid breathing any fine particulates.
17. IR was used to follow alkyne consumption, and methanolic solutions obscured the alkyne CH stretch. As a result, a toluene solution of ester 5 was used instead of carboxylate 6.
18. With the complex 1, the solution turned blue-green.
19. In this study, we quantitated total ruthenium content in the plasma and did not use MS to separate isotopes.
20. 1 μg of Ru detected in a 5 mg sample corresponds to 200 ppm Ru.
21. 2, 0.8 mL (6.44 mmol, 6.2 equiv) of 1-hexene, and 43.3 mg of Grubbs' complex 2 (0.051 mmol, 5 mol %). The reaction was stirred at rt for 2 h. After this time, the mixture was treated with a solution of 38.8 mg of 6 (0.315 mmol, 31 mol % or 6.2 equiv based on 2) in 1.0 mL of methanol. The color of the solution changed from purple to yellow within 5 min. The reaction mixture was stirred for 30 min at rt, concentrated in vacuo (rotary evaporator), and purified by column chromatography on approximately 10 g of silica gel (2.0 g of silica gel was used for every 0.01 mmol of catalyst used), using 1:8 ethyl acetate - hexanes as the eluent.
22. Smulik, J. A.; Diver, S. T.; Pan, F.; Liu, J. Org. Lett. 2002, 4, 2051 -2054.
23. Further studies are in progress.
24. 2) = 1.02.
25. 3P complex of 2 (Grubbs' Ru gen-2), see the Supporting Information for details.