Introduction
Ruthenium(III) chloride and its hydrate (RuCl3·xH2O) are well-known catalysts for the oxidation of functional groups in organic synthesis. Some of these transformations include: alkenes to diols
[1]
and α-hydroxyketones,
[2]
sulfides to sulfones,
[3]
as well as alkynes,
[4]
alcohols
[5]
and aryl groups
[6]
to their corresponding carboxylic acids. The titled catalyst has also been used for the desymmetrization of aryl and benzyl diselenides,
[7]
aldol condensation,
[8]
formation of α-aminonitriles (Strecker reaction),
[9]
acylation,
[10]
acetal formation,
[11]
aryl
[12]
or azide
[13]
reductions, conjugate addition reactions
[14]
and C-C bond formations.
[15]
Apart from the use of ruthenium(III) chloride in functional group manipulation, recent work has used RuCl3 in the formation of polypyridine complexes, suggesting that this reagent may soon experience a wider application in metallopolymer and molecular-device synthesis.
[16]
Ruthenium(III) chloride is also a critical ingredient for preparing a number of ruthenium-based catalysts, including Grubbs’ catalysts (widely applied in metathesis reactions)
[17]
and ruthenium-phosphine complexes capable of selective reductions.
[18]
Both anhydrous and hydrated forms are commercially available as solids. Alternatively, the solids may be prepared by heating powdered ruthenium metal to temperatures greater than 700 °C in the presence of chlorine gas; on cooling, dark brown to black crystals may form.
[19]
Although their hygroscopic nature mandates storage in desiccated environments, no additional precautions are required for safe handling.
