Arene chromium tricarbonyl complexes direct synthesis

In one indirect route to T -arene chromium tricarbonyl complexes, an incompatible or reactive functionality is protected in the free arene precursor. Complexation of the protected ligand, followed by deprotection, gives the desired complex. This method is particularly effective, for example, for the synthesis of complexes with ketone or aldehyde functions where the carbonyl group is protected as an acetal. A typical example is represented in Scheme 6.3. By comparison, the direct complexation reaction under standard conditions [Cr(CO)g, n-Bu20/THF, reflux, 5 h] afforded the corresponding complex in 4% yield only. ... 

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