[15038-48-9] · C9H9MoN3O3 · Tris(acetonitrile)tricarbonylmolybdenum · (MW 303.15)
(reductively cleaves the N-O bond of isoxazolines1)
Physical Data: mp 140 °C (dec).
Solubility: sol acetonitrile and THF.
Form Supplied in: yellow crystals; not commercially available.
Preparative Methods: by refluxing Hexacarbonylmolybdenum in Acetonitrile in an inert atmosphere. Removal of solvent under an inert atmosphere yields tris(acetonitrile)tricarbonylmolybdenum.2
Purification: the crude solid obtained in the above preparation is typically used without further purification.
Handling, Storage, and Precautions: air and thermally sensitive; pyrophoric; molybdenum(0) is reputed to be of low toxicity. Use in a fume hood.
Treatment of isoxazolines with tris(acetonitrile)tricarbonylmolybdenum followed by silica gel leads to 3-hydroxy ketones (eq 1).1 The conversion occurs under much milder conditions than when hexacarbonylmolybdenum is employed. The reaction is most efficient with spiro-fused cyclopropyl derivatives, where dehydration is disfavored. In other systems, mixtures of 3-hydroxy ketones and a,b-unsaturated ketones are obtained.
Treatment of 2-chloroacetophenone with tris(acetonitrile)tricarbonylmolybdenum, followed by cyclopentadienyllithium, affords a mixture of the aldol product (1) and the secondary aldol product (2) (eq 2).3 No demetallation studies have been reported for the resulting molybdenum complex. Only the yield after recrystallization was reported, suggesting that the efficiency of this reaction may be higher than indicated.
James W. Herndon
University of Maryland, College Park, MD, USA