Synthetically useful sonochemical reactions in solution

Examples of sonochemical reactions in solution with synthetic potential have recently been published. The free radical mechanism of some of them seems to be clearly established, in accordance with the empirical sonochemistry rules. Cases exist, however, where this simple interpretation is difficult. This is particularly true for cycloaddition reactions. In the case of [2+2] cycloaddition, the steric course is modified. In [4+2] reactions, positive results have been recorded with quinones as the dienophile. A few questions left open using current theories are identified and possible mechanistic pathways are discussed considering the radiomimetic effect of sonication.