Iron oxide-catalysed transformations

From the perspective of sustainability, magnetite and iron(iii) oxide are perhaps the ultimate transition-metal catalysts. Magnetite and iron(iii) oxide are both naturally occurring oxides on Earth, and as such, they are tremendously abundant and highly inexpensive ca. 4/kg Fe304, 3/kg FeaOg). In efforts to generate new and more sustainable chemical 

Despite the low cost and availability of magnetite, its use in catalysis has been somewhat limited to alkene isomerisation, water gas shift chem-istry, Fischer-Tropsch synthesis and alkane dehydrogenation. However, several interesting nanoparticulate-magnetite-catalysed synthetic transformations have been reported.  

Song used nanoparticulate-magnetite as the catalyst for an oxidative aza-Henty reaction, for the coupling of two unique C(sp )-H bonds, using oxygen 

Other magnetite-catalysed transformations have also been reported Yus reported a one-pot multieomponent aza-Sakurai reaction, and in later work reported the direct amination of benzylic-alcohols.  

Use of iron(iii) oxide has been reported for a number of other organic transformations, most notably a 3-component aldehyde, alkyne and amine coupling, and for the C(sp )-H borylation of arenes using bis(pinacolato)diboron.  

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The bis-(o-formylphenyl)phosphine (108) undergoes a mechanistically intriguing acid-catalysed reaction with water to form (109). This appears to be closely related to the previously observed hydration of u-(phenylethynyl)phenyl-phosphines. Reactions of the latter with iron carbonyls have now been shown to involve transformation of the acetylenic units to form the cyclopentadienone structure (110), isolated as the phosphine oxide. ... 

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