Synthetic applications of microwave assisted reactions with gas reagents.
Maurizio Taddei, Dipartimento Farmaco Chimico Tecnologico. Università degli Studi di Siena, 53100 Siena, Italy.

Amongst different reaction conditions tested inside a microwave cavity, nowadays it is possible to carry out reactions that use gases as one of the reagents. Most of the reactors for microwaves are designed to work under the pressure developed by the solvent under heating, thus, the reaction tube can be considered as a potential small autoclave that could be used for reaction with gas. This technique could be applied safely to hydrogenation, (including hydrogenolysis), carbonylation, carboxylation and hydroformylation. With the high potential of speed up all these versatile organic transformations, we investigated several synthetic applications to multicomponent reactions, synthesis of pharmaceutically relevant heterocycles and natural products synthesis. We found that it is possible to design new synthetic approaches to natural products employing microwaves in several steps, shortening the synthesis as a new tool to chemical production of natural products libraries. Moreover some of these microwave assisted reactions were stereoselective as the corresponding transformations carried out at room temperature encouraging the extension of microwaves dielectric heating to reactions that proceed through a substrate controlled stereochemical path.