Solvent-free organic syntheses - using supported reagents and microwave irradiation

Recent developments in microwave-accelerated solventless organic syntheses are summarised. This expeditious and solvent-free approach involves the exp osure of neat reactants to microwave (MW) irradiation in conjunction with t he use of supported reagents or catalysts which are primarily of mineral or igin. The salient features of these high yield protocols are the enhanced r eaction rates, greater selectivity and the experimental ease of manipulatio n. Among other reagents recently described in the literature on this eco-fr iendly green approach, the use of recyclable mineral oxides or supported re agents from our laboratory such as Fe(NO3)(3)-clay (clayfen), Cu(NO3)(2)-cl ay (claycop), NH4NO3-clay (clayan), NH2OH-clay, PhI(OAc)(2)-alumina, NaIO4- silica, CrO3-alumina, MnO2-silica, NaBH4-clay, etc. are highlighted in MW-p romoted deprotection, condensation, cyclization, rearrangement, oxidation a nd reduction reactions including the rapid one-pot assembly of heterocyclic compounds from in situ generated intermediates.