Silica sulfuric acid and silica chloride as efficient reagents for organic reactions

Silica sulfuric acid and silica chloride, two silica based solid acids have been used for various organic functional group transformations either as reagent or as catalyst. All reactions have been carried out under mild and heterogeneous conditions. These reagents were used for C-C, C-N, and C-O bond formation and cleavage and also deprotection of different protecting groups. Silica sulfuric acid was recycled in many cases, and reused. Silica chloride has been used as a starting material for preparation of some new silica based reagents with special properties.