Microwave irradiation of chalcones under solvent-free conditions resulted in a "green-chemistry" procedure for the preparation of flavanones in very good yields. Using an unmodified household microwave oven, different mineral supports and catalysts were tested. By irradiation of chalcones with 30% TFA over silica gel, eleven known flavanones and five new compounds were prepared in high yields.
cyclization; flavanones; Michael addition; microwave; silica gel
