| Abstract
| - A mild and efficient electron-transfer method was developed for the chemoselective reduction ofaromatic nitro groups using samarium(0) metal in the presence of a catalytic amount of 1,1‘-dioctyl-4,4‘-bipyridinium dibromide. This method was found to give the product aromatic amine in 79−99% yield with selectivity over a number of other functional and protecting groups such as alkene,azide, benzyl ether, nitrile, amide, halide, p-toluenesulfonamide, t-Boc, tert-butyldiphenylsilyl ether,and aliphatic nitro groups. Our results also indicate that samarium(0) plays an important role inthe reduction process and that 1,1‘-dioctyl-4,4‘-bipyridinium dibromide acts as an electron-transfercatalyst and is essential in the activation of samarium(0) metal. The major active reducing agentresponsible for the reduction is believed to be the radical cation species formed from 1,1‘-dioctyl-4,4‘-bipyridinium dibromide.
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