In situ preparation of a highly active N-heterocyclic carbene-coordinated olefin metathesis catalyst

Organic Letters

Volumn 2, Issue 20, 2000, Pages 3153-3155

  Morgan, John P ^a   Grubbs, Robert H ^a  

^a CALIFORNIA INSTITUTE OF TECHNOLOGY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALKENE; DYES, REAGENTS, INDICATORS, MARKERS AND BUFFERS; HETEROCYCLIC COMPOUND; HYDROCHLORIC ACID;

ARTICLE; CATALYSIS; CHEMISTRY; SYNTHESIS;

ALKENES; CATALYSIS; HETEROCYCLIC COMPOUNDS; HYDROCHLORIC ACID; INDICATORS AND REAGENTS;

EID: 0034609694     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0063510     Document Type: Article

References (31)

1. For recent reviews on olefin metathesis, see: (a) Grubbs, R. H.; Chang, S. Tetrahedron 1998, 54, 4413-4450.
2. (b) Randall, M. L.; Snapper, M. L. J. Mol. Catal. A-Chem. 1998, 133, 29-40.
3. (c) Trnka, T. M.; Grubbs, R. H. Acc. Chem. Res., in press.
4. (a) Schwab, P.; France, M. B.; Ziller, J. W.; Grubbs, R. H. Angew. Chem., Int. Ed. Engl. 1995, 34, 2039-2041.
5. (b) Schwab, P.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1996, 118, 100-110.
6. (a) Schrock, R. R.; Murdzek, J. S.; Bazan, G. C.; Robbins, J.; DiMare, M.; O'Regan, M. J. Am. Chem. Soc. 1990, 112, 3875-3886.
7. (b) Bazan, G. C.; Khosravi, E.; Schrock, R. R.; Feast, W. J.; Gibson, V. C.; O'Regan, M. B.; Thomas, J. K.; Davis, W. M. J. Am. Chem. Soc. 1990, 112, 8378-8387.
8. (c) Bazan, G. C.; Oskam, J. H.; Cho, H. N.; Park, L. Y.; Schrock, R. R. J. Am. Chem. Soc. 1991, 113, 6899-6907.
9. (a) Weskamp, T.; Schattenmann, W. C.; Spiegler, M.; Herrmann, W. A. Angew. Chem., Int. Ed. Engl. 1998, 37, 2490-2493. Also see corrigenda: Angew. Chem., Int. Ed. Engl. 1999, 38, 262.
10. (b) Scholl, M.; Trnka, T. M.; Morgan, J. P.; Grubbs, R. H. Tetrahedron Lett. 1999, 40, 2247-2250.
11. (c) Huang, J.; Stevens, E. D.; Nolan, S. P.; Petersen, J. L. J. Am. Chem. Soc. 1999, 121, 2674-2678.
12. Scholl, M.; Ding, S.; Lee, C. W.; Grubbs, R. H. Org. Lett. 1999, 1, 953-956.
13. (e) Grubbs, R. H.; Trnka, T. M. Abstr. Pap. Am. Chem. Soc. 2000, 219:130-INORG, Part 1.
14. (a) Chatterjee, A. K.; Morgan, J. P.; Scholl, M.; Grubbs, R. H. J. Am. Chem. Soc. 2000, 722, 3783-3784. For related studies with unsaturated imidazol-2-ylidenes, see:
15. (b) Fürstner, A.; Thiel, O. R.; Ackermann, L.; Schanz, H. J.; Nolan, S. P. J. Org. Chem. 2000, 65, 2204-2207.
16. (c) Briot, A.; Bujard, M.; Gouverneur, V.; Nolan, S. P.; Mioskowski. C. Org. Lett. 2000, 2, 1517-1519.
17. For the preparation of 1,3-disubstituted imidazol-2-ylidenes such as 4a and 4b. see: (a) Arduengo, A. J.; Goerlich, J. R.; Marshall, W. J. J. Am. Chem. Soc. 1995, 117, 11027-11028.
18. (b) Arduengo, A. J.; Krafczyk, R.; Schmutzler, R.; Craig, H. A.; Goerlich, J. R.; Marshall, W. J.; Unverzagt, M. Tetrahedron 1999, 55, 14523-14534.
19. (c) Arduengo, A. J.; Dias, H. V. R.; Harlow, R. L.; Kline, M. J. Am. Chem. Soc. 1992, 114, 5530-5534.
20. Jafarpour, L.; Nolan, S. P. Organometallics 2000, 19, 2055-2057.
21. In this paper, the phrase "in situ catalyst" refers to a catalyst system that is constructed from many distinct components and then used in the same reaction vessel. It does not refer to single-component catalysts (i.e., allenylidenes), which are thermally or photochemically activated in situ. For the latter cases, see: (a) Picquet, M.; Touchard, D.; Bruneau, C.; Dixneuf, P. H. New J. Chem. 1999, 23, 141-143.
22. (b) Picquet, M.; Bruneau, C.; Dixneuf, P. H. Chem. Commun. 1998, 2249-2250.
23. (a) Dias, E. L.; Nguyen, S. T.; Grubbs, R. H. J. Am. Chem. Soc. 1997, 119, 3887-3897. For the use of HCl as phosphine scavenger, see:
24. (b) Lynn, D. M.; Mohr, B.; Grubbs, R. H. J. Am. Chem. Soc. 1998, 120, 1627-1628.
25. (c) Lynn, D. M.; Mohr, B.; Grubbs, R. H.; Henling, L. M.; Day, M. W. J. Am. Chem. Soc. 2000, 122, 6601-6609.
26. 3, and other Lewis acids as potential phosphine scavengers, see: (a) Sanford, M. S.; Henling, L. M.; Grubbs, R. H. Organometallics 1998, 17, 5384-5389.
27. (b) Katayama, H.; Yoshida, T.; Ozawa, F. J. Organomet. Chem. 1998, 562, 203-206.
28. 6 were dried and degassed prior to use and stored over molecular sieves. The concentration of all reagents was identical to those used in the experiments of Table 1. NMR spectra were recorded with Varian VNMR software on an Oxford 300 MHz instrument.
29. 3 may also play a similar role. For a related example of Lewis acid activation of carbonyl-containing substrates, see: Fürstner, A.; Langemann, K. J. Am. Chem. Soc. 1997, 119, 9130-9136.
30. A typical experimental procedure is as follows. A suspension of tetrafluoroborate salt 5 (14 mg, 35 μmol) in dry THF (1 mL) was prepared in a flame-dried Schlenk flask under nitrogen. Potassium tert-butoxide (4 mg, 35 μmol) was added to the rapidly stirred suspension at room temperature, resulting in the immediate dissolution of 5 to form a yellow solution. After 5 min, a solution of 1 (21 mg, 25 μmol) in dry benzene (2 mL) was added via cannula. The mixture was heated to 80°C for 35 min and subsequently cooled to room temperature. Methyl vinyl ketone (100 μL, 1.3 mmol), 5-hexenyl acetate (84 μL, 0.5 mmol), and HCl (2.0 M in diethyl ether, 60 μL, 120 μmol) were added to the cooled solution via syringe. The reaction mixture was then heated to 45°C for 14 h, followed by concentration in vacuo to a brown residue. Purification by silica gel chromatography (9: 1 hexanes: ethyl acetate) yielded 90% of 6 (84 mg, 0.45 mmol) as a clear, yellowish oil.
31. Catalyst 1 and the imidazolium tetrafluoroborate salt 5 will be available from Strem Chemicals, Inc. soon.