General procedure for the synthesis of methyl 4-formylphenylacetate from methyl 2-(4-(hydroxymethyl)phenyl)acetate: a solution was formed by dissolving Dess-Martin Periodinane (1.5 eq.) in dichloromethane (0.3 M) at room temperature and protected by nitrogen with stirring. Subsequently, a dichloromethane (0.2 M) solution of methyl 2-(4-(hydroxymethyl)phenyl)acetate was added to this solution. After the reaction was carried out for 4 hours, the reaction mixture was diluted with ether (0.1 M). Next, the reaction mixture was poured into a saturated sodium bicarbonate (0.5 M) solution containing sodium thiosulfate (10.5 equivalents) and stirred for 30 minutes. The organic and aqueous phases were separated and the organic phase was washed sequentially with saturated sodium bicarbonate solution (1 liter), water (1 liter) and brine (1 liter). The washed organic phase was dried with sodium sulfate, filtered and concentrated in vacuum to afford the target product methyl 4-formylphenylacetate in 94% yield. The product was characterized by 1H NMR (400 MHz, CDCl3): δ 10.00 (s, 1H), 7.86 (d, 2H), 7.46 (d, 2H), 3.72 (m, 5H).
