Doped sol-gel materials as heterogeneous reagents for organic synthesis

We advance the use of reactive doped sol-gel materials as heterogeneous rea gents for organic-chemistry synthesis. Three approaches were demonstrated w ith SiO2-based materials: Direct physical entrapment of the organic reagent ; in-situ generation of an inorganic reagent within the matrix; and covalen t attachment of the reagent to the matrix. With the first, entrapped p-tolu enesulfonic acid facilitated the 100% yield esterification of benzoic acid with 1-pentanol, and the 100% dehydration of 1-tetralol to 1,2-dihydronapht halene; with the second approach, a sol-gel oxidant, SiO2/MnO2 was used to convert benzyl alcohol to benzaldehyde and 1-tetralol to 1-tetralone; and w ith the third, anchored propylamine facilitated dehydrobromination reaction s resulting in double-bond formation. Several other reactions with these re agents are described, and their reactivities analyzed.