Microwave-assisted Solventless Synthesis of Heterocycles

The first example of a reaction between two solids, under solvent-free and catalyst-free conditions, was demonstrated [41] when the reaction of neat 5- or 8-oxobenzo- 

2-15) [32]. Although the separation employs an organic solvent to obtain pure olefin, it is still a useful protocol in the total synthesis. Similarly, several phosphonium salts, stabilized as well as non-stabilized, have been prepared in a domestic MW oven [51] 

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