The general procedure for the synthesis of 2,3-dihydrobenzofuran-7-carbaldehyde using 2,3-dihydrobenzofuran-7-methanol as starting material was as follows: 2,3-dihydrobenzofuran-7-methanol (9.76 g, 64.99 mmol) was mixed with manganese dioxide (45.2 g, 519.93 mmol) in toluene (250 mL), and the reaction was stirred for 3 hours at 60 °C. Upon completion of the reaction, manganese dioxide was removed by filtration and the filtrate was concentrated under reduced pressure. Subsequently, the precipitate precipitated was collected by filtration and washed with cooled hexane to give 2,3-dihydrobenzofuran-7-carbaldehyde (7.43 g, 50.1 mmol, 77% yield) as a light yellow solid.