A most user-friendly protocol for ring closing metathesis reactions

Abstract

Ring closing metathesis reactions (RCM) can be conveniently achieved in a photo-assisted manner simply by heating a solution of the diene substrate, catalytic amounts of commercially available [(p-cymene)RuCl₂]₂ 4 and PCy₃ in CH₂Cl₂ under neon light.

References

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3. For recent reviews on applications in polymer chemistry see: D. Tindall, J. H. Pawlow and K. B. Wagener, Top. Organomet. Chem., 1998, 1, 180; L. L. Kiessling and L. E. Strong, Top. Organomet. Chem., 1998, 1, 196 and references cited therein.
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9. Constant irradiation of the reaction mixture with a UV emitting quartz lamp dipped into the solution at room temperature is inappropriate, leaving 98% of the substrate unchanged after 16 h reaction time.
10. Reaction of N,N-bis(allyl)toluene-p-sulfonamide in refluxing CH₂Cl₂ with 4(2.5 mol%) and PCy₃(5.5 mol%) in the dark shows that 92% of the substrate (GC) is unchanged after 16 h. Note that after this period of time, the photoassisted reaction is quantitative.†.
11. RCM can also be carried out in toluene at 80 °C; in this medium, however, the reactions tend to be less selective as shown by the following prototype experiment: (graphic not included..
12. For an in-depth study on the effect of substitution on RCM see: T. A. Kirkland and R. H. Grubbs, J. Org. Chem., 1997, 62, 7310.
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