Molybdenum(V) Chloride-Zinc

MoCl5-Zn
(MoCl5)

[10241-05-1]  · Cl5Mo  · Molybdenum(V) Chloride-Zinc  · (MW 273.19) (Zn)

[7440-66-6]  · Zn  · Molybdenum(V) Chloride-Zinc  · (MW 65.39)

(nitro group, N-oxide reduction;5 amine preparation4)

Physical Data: see Molybdenum(V) Chloride and Zinc.

Solubility: MoCl5: sol organic solvents. Zn: insol.

Form Supplied in: MoCl5: green-black solid; widely available. Zn: metallic solid; widely available as powder, wire, or granular solid.

Handling, Storage, and Precautions: MoCl5 is air- and moisture-sensitive and somewhat corrosive. Use in a fume hood.

Sulfoxide Reduction by Low-Valent Molybdenum Species.

Olah reported that treatment of a THF solution of MoCl5 with H2O followed by Zn metal produces a low-valent molybdenum species which effectively converts organic sulfoxides to sulfides at room temperature in high yields (78-91%). The active deoxygenating species in solution is believed to be some form of MoIII. Vanadium(II) Chloride was found to mediate the same deoxygenation, although somewhat less efficiently.1 Sulfoxide reduction has also been reported for low-valent molybdenum and tungsten species obtained by other means.2,3

Deoxygenation of N-Oxides and Reduction of Nitro Groups.4

Molybdenum(V) Chloride-Zinc is a mild, selective reagent for the deoxygenation of pyridine and pyridazine N-oxides and for the reduction of aromatic and heteroaromatic nitro groups to amines. Reported yields are moderate (29-71%); however, potentially sensitive functionality is tolerated (eqs 1-3).

Other Reductions Mediated by Low-Valent Transition Metal Species.

The reduction of organic compounds by low-valent transition metal species has been reviewed by Ho.5


1. Olah, G. A.; Prakash, G. K. S.; Ho, T.-L. S 1976, 810.
2. Ho, T.-L. SC 1977, 7, 321.
3. Nuzzo, R. G.; Simon, H. J.; San Filippo, J. J. JOC 1976, 42, 568.
4. Polanc, S.; Stanovnik, B.; Tisler, M. S 1980, 129.
5. Ho, T.-L. S 1979, 1.

William E. Crowe

Emory University, Atlanta, GA, USA



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