Zinc powder aromatics acylation

Zinc powder (100% mol) without any treatment promotes Friedel-Crafts acylation of aromatic compounds with acyl chlorides to afford the corresponding aromatic ketones in high yield. Acetylation and benzoylation of a great number of both activated and deactivated aromatic compounds... 

Table 3.14 Acylation of aromatics with acetyl and benzoyl chlorides in the presence of zinc powder under microwave irradiation...

A much more environmentally sound procedure was advocated by Paul et al. [164], who used Zn powder as a catalyst for Friedel-Crafts acylation of aromatic compounds. Zinc is a nontoxic, safe, and inexpensive metal which can be used in solvent-free conditions. It was shown to have a remarkably high activity in the acylation of a series of aromatic compounds with acetyl and benzoyl chlorides when performed under microwave irradiation. Yields were much more better than when using conventional thermal heating (Eq. (80), Table 4.28). The Zn powder could also be re-used up to six times after simple washing with diethyl ether and dilute HCl. 

The reduction of nitroarenes to azoxy compounds ArN=N(0)Ar is promoted by bismuth tiichloiide/powdered zinc. Aromatic amines are formed in excellent yields in the reduction of nitroarenes with BH3/NiCl2 or nickel boride . Acyl, ester, amide and cyano groups are not affected. Reaction of the nitro compounds RCH2NO2 (R = Ph, Bz... 

Keywords Aromatic compounds, acid chlorides, zinc oxide powder, solvent-free, room temperature, Friedel-Crafts acylation, acyl derivatives... 

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