Ultrasound Promoted Stereoselective Synthesis of 2,3-Dihydrobenzofuran Appended Chalcones at Ambient Temperature

In the present investigation, an ultrasound promoted the synthesis of a series of (E)-3-(2,3-dihydrobenzofuran 5-yl)-1-(aryl)prop-2-en-1-one derivatives from 2,3-dihydrobenzofuran-5-carbaldehyde and various aromatic ketones under clean conditions. The application of ultrasound irradiation in organic reactions is one of the incredible tools of green chemistry as reactions can be carried out rapidly under neat conditions. A library of a novel (E)-3-(2,3-dihydrobenzofuran-5-yl)-1-(aryl)prop-2-en-1-one chalcone derivatives were synthesized in good to excellent yield under ultrasonic irradiation. The structures of all synthesized chalcone derivatives synthesized in this study have been established by using FT-IR, NMR, C-13 NMR, and FIRMS techniques. The stereochemistry around C=C in the chalcones was shown to be trans by H-1 NMR (J(ab) = 15.5Hz). The benefits of the present synthesis include mild reaction conditions, high yield, purification by non-chromatographic strategy and short reaction times, demonstrating the significance of this protocol in terms of waste reduction and energy efficiency.