Transfer Catalysis Between Two Solids: Application to the Reduction of Nitroarenes.

A wide range of aromatic nitro compounds can be reduced to anilines through the use of a Cr(II)/Mn(0) redox couple in the presence of trimethylsilyl chloride [TMSCl, Eq. (1)]. Only 0.25 equivalents of chromium are required to reduce solid-supported nitroarenes (R=solid support); this represents a rare case of transfer catalysis between two solid phases. The reaction is also amenable to solution-phase synthesis (R=OH).