Step 1: A mixture of triethyl phosphite (1.45 g, 8.70 mmol) and 1-(bromomethyl)-3-methoxybenzene (1.50 g, 7.50 mmol) was stirred and reacted at 90 °C overnight under nitrogen protection. After completion of the reaction, the mixture was cooled to room temperature to afford the yellow oily product diethyl 3-methoxybenzylphosphonate (1.84 g, 95.9% yield). The product did not require further purification and could be used directly in the next step of the reaction. The product was characterized by the following spectral data: mass spectrum (ESI, positive ion mode) m/z: 259.2 ([M + H]+); exact mass of molecular formula C12H19O4P: 258.10.
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