The information given below was retrieved and reworked from the publication: Synthesis of Methoxyfumimycin with 1,2-Addition to Ketimines by Patrick J. Gross, Caroline E. Hartmann, Martin Nieger and Stefan Bräse. https://doi.org/10.1021/jo902026sBoric acid (3.22 g, 52.0 mmol, 5.00 eq.) was suspended in THF (30 mL), H2O2 (30% in H2O, 3.4 mL) and H2SO4 (1.5 mL). After stirring for 30 min, 4-(allyloxy)-3-methoxybenzaldehyde (2.00 g, 10.4 mmol, 1.00 eq.) was added as solution in THF (10 mL) within 15 min. After additional stirring for 5 h, the mixture was filtrated. The filtrate was neutralized by addition of sat. NaHCO3 solution (100 mL); the aqueous layer was extracted with EtOAc (3 × 50 mL). The combined organic extracts were washed with brine (50 mL), dried over Na2SO4 and concentrated under reduced pressure. Flash chromatography (cyclohexane:EtOAc 4:1→3:1) afforded 3-methoxy-4-prop-2-enoxy-phenol as brown oil (1.48 g, 81%).Analysis of the target compound: 1H NMR (500 MHz, CDCl3): δ = 3.80 (s, 3H), 4.52 (dm, J = 5.6 Hz, 2H), 5.12 (br. s, 1H), 5.25 (dq, J = 10.4, 1.3 Hz, 1H), 5.36 (dq, J = 17.3, 1.5 Hz, 1H), 6.08 (ddt, J = 17.3, 10.5, 5.6 Hz, 1H), 6.31 (dd, J = 8.6, 2.8 Hz, 1H), 6.46 (d, J = 2.8 Hz, 1H), 6.75 (dd, J = 8.6 Hz, 1H). 13C NMR (125 MHz, CDCl3): δ = 55.8, 71.1, 100.7, 105.9, 115.5, 117.8, 133.7, 141.9, 150.5, 150.6. IR (KBr): ν–1 = 3360, 2940, 2603, 1607, 1455, 1217, 952, 722 cm–1. MS (EI), m/z (%): 180 (44) [M+], 139 (100) [C7H7O3+]. HRMS (EI) for C10H12O3: calcd. 180.0786; found 180.0786.
