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Please login to access the full content or check if you have access via20.5.1.7.12.1 Method 1: Metathesis with Tungsten-Based Catalysts
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Zhang, M.; Hanson, P. R., Science of Synthesis, (2007) 20, 920.
Phenoxytungsten complexes catalyze inter- and intramolecular metathesis reactions of simple alkenoates and alkadienoates, respectively. Chloro(diethyl ether)bis(2,6-diphenylphenoxy)neopentyl(neopentylidene)tungsten(VI) was one of the first examples of tungsten complexes that are well-defined, Lewis acid free, homogeneous alkene-metathesis catalysts, and shows moderate activity for the metathesis of ethyl oleate with dec-5-ene.[320] A better result can be achieved when tetrachlorobis(2,6-dichlorophenoxy)tungsten(VI) associated with a Lewis acid (Bu4Pb or Me4Sn) is employed as catalyst (Scheme 74).[321,322] In 1995, trans-dichlorobis(2,6-dibromophenoxy)oxotungsten(VI), prepared in situ from tetrachloro(oxo)tungsten(VI) and 2 equivalents 2,6-dibromophenol, was found to catalyze ring-closing metathesis of nonconjugated dienes, e.g. 219, to form the corresponding cycloalkenes, e.g. 220 (Scheme 78).[323,324]
Meeeee 88 Meeee- eee Meee-Meeeeee Meeeeeeeee ee Meeeeeeeee Meeeeeeee ee Meeeeeee Meeeeeeee[888–888]
Meeee eeeeeeee eeeeeeeee eeeeeee eeeeeee eeeeee, e.e. eeeeeeeeeeeeeeeeee(MM) ee eeeeeeeeeee(eee)eeeeeeee(MM) eeeeeeeee ee 8,8,8,8-eeeeeeeeeee-8,8-eeeeeeeeeeeeeeeee eeeee eee eeeeeeeeee ee eeeeeee eeeeeeeeeeeeee eeeeeee eeee eeeee eeeeee eeeeeeeee eeeeee ee eeeee eeeee.[888] Meeeeeeeeeeeeeee eee eeeee eeeeeeeeee ee eeeee eeee-8-eeeeee eeee eeeeee eee eeeeee eeeeeee eeeee ee eeee eeeeee eee eeeeeeeeeeeee eeee eeee eeeeeeeee eeeeee.
Meeeeeeeeeee Meeeeeeee
Meeeeee Meeeeeeee-8-eee-8,8-eeeeeeeeeeeee (888, M8 = MM8Me); Meeeeee Meeeeeeee:[888,888]
M 888-eM eeeee-eeeeeeee eeeee eee eeeeeee eeee MMMe8 (8.88 e, 8.8 eeee), 8,8-eeeeeeeeeeeee (8.88 e, 8.8 eeee), eee eeeeeee (88 eM). Mee eeeeeee eee eeeeeeee eee 8 e, eee eee eeeeeee eee eeeeeee ee e eeeeee eeeeeeeeee. Mee eeeee eeeeeee eee eeeeee ee eeee e eeeeeee eee eeeee eeeee eeee eeeeee eee 88 eee. Me eee eeeee eeee eeeee 888 (M8 = MM8Me; 88.8 e, 88.8 eeee), Me8Me (8.88 e, 8.8 eeee), eee eeeeeee (88 eM). Mee eeeeeee eee eeeeee ee e 88°M eee eeee eee 8 e. Meeee eeeeeee, eee eeeeeee eee eeeeeeee (eeeeee eee, 888–888 eeee, ee. 8-ee eee), eee eee eeeeee eee eee eeeeee eeee eeeeeeeeee eeeeeee (88 eM). Mee eeeeeeee eeeeeee eeee eee eeeeee eeee 8% ee MeMM (88 eM) eee M8M (88 eM). Mee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee, eee eee eeeeeee eee eeeeeeee ee eeeeeeeeeeee; eeeee: 88.88 e (88%); ee 88–88°M/88 Meee.
References
[320] | Meeeeeee, M.; Meeeeee, M.; Meeeee, M.-M., M. Meee. Mee., Meee. Meeeee., (8888), 8888. |
[321] | Meeeeeee, M.; Meeeeee, M.; Meeeee, M.-M., M. Mee. Meeee., (8888) 88, 88. |
[322] | Meeee, M. M.; Meeeee, M. M., Meee. M. Meee., (8888) 88, 888. |
[323] | Meeeee, M. M.; Meeeeee, M.; Meeeeeeee, M. M., M. Me. Meee. Mee., (8888) 888, 8888. |
[324] | Meeeeeee, M. M.; Meeeee, M. M.; Meeeeeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[325] | Meeeeeeee, M. M.; Meeeee, M. M., M. Mee. Meeee., (8888) 88, 888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) M 88-8, 8888.
- 8.Meeeee-Meee, (8888) M 88-8, 8888.
- 8.Meeeee-Meee, (8888) M 88-8, 8888.