## 2 Materials and Methods
### Chloromethyllation
H\({}_{2}\)SO\({}_{4}\) (0.5 mL) at 100 \({}^{\circ}\)C for 6 h. Filtration on a P3 glass filter allowed the isolation of the product as a pink solid in 60% yield. \({}^{1}\)H NMR (600 MHz, CDCl\({}_{3}\)) \(\delta\)(ppm): 7.93 (s, 2H, Ar-H), 6.28 (s, 1H, Ar-OH), 4.72 (s, 4H, Ar-CH\({}_{2}\)-Cl), 2.58 (s, 3H, Ar-C(=O)-CH\({}_{3}\)). \({}^{13}\)C NMR (600 MHz, CDCl\({}_{3}\)) \(\delta\)(ppm): 196.2 (C=O), 157.5 (C-Ar), 131.8 (C-Ar), 130.5 (C-Ar), 124.7 (C-Ar), 42.0 (-CH\({}_{2}\)-), 26.5 (CH\({}_{3}\)). EA found: C 51.67%, H 4.15%; calcd for (C\({}_{10}\)H\({}_{10}\)O\({}_{2}\)Cl\({}_{2}\)): C 51.53%, H 4.32%. Mp n.d. (decomposed). 4-Allyl-2,3-bis(chloromethyl)-6-methoxyphenol (**2d**). Following the general procedure, eugenol (10 mmol) was stirred with PF (32 mmol), conc. HCl (37%, 20 mL), and DCM (2.0 mL) at 25 \({}^{\circ}\)C for 4 h. Following extraction with DCM, a highly impure material was obtained, contaminated by unreacted eugenol and diverse polycondensation byproducts. Several purification methods were attempted to obtain a pure product, without complete success (see Figure S4). The product was finally obtained as a viscous black liquid in 50% yield. \({}^{1}\)H NMR (600 MHz, CDCl\({}_{3}\)) \(\delta\)(ppm): 6.68 (s, 1H, Ar-H), 5.98 (m, 1H, -CH=C), 5.30 (s, 1H, Ar-OH), 5.10 (m, 1H, -C=CH\({}_{2}\)), 5.02 (m, 1H, -C=CH\({}_{2}\)) 4.87 (s, 2H, Ar-CH\({}_{2}\)-Cl), 4.74 (s, 2H, Ar-CH\({}_{2}\)-Cl), 3.89 (s, 2H, Ar-OCH\({}_{3}\)), 3.46 (s, 2H, Ar-CH\({}_{2}\)-C=C). \({}^{13}\)C NMR (400 MHz, CDCl\({}_{3}\)) \(\delta\)(ppm): 150.3 (C-Ar), 141.6 (C-Ar), 136.0 (+CH\({}_{2}\)), 129.8 (C-Ar), 127.6 (C-Ar), 125.9 (C-Ar), 116.3 (=CH\({}_{2}\)), 113.4 (C-Ar), 56.1 (OCH\({}_{3}\)), 39.9 (-CH\({}_{2}\)-), 38.5 (-CH\({}_{2}\)-), 37.7 (-CH\({}_{2}\)-). EA found: C 55.35%, H 5.22%; calcd for (C\({}_{12}\)H\({}_{14}\)O\({}_{2}\)Cl\({}_{2}\)): C 55.19%, H 5.40%. 2,3,4-Tris (chloromethyl)-6-methoxyphenol (**2e**). Following the general procedure, guaiacol acetate (**1e**, 10 mmol) was stirred with PF (42 mmol), conc. HCl (37%, 25 mL), and DCM (2.5 mL) at 40 \({}^{\circ}\)C for 6 h. After extraction with DCM, the product was obtained as a dark brown solid in 60% yield. \({}^{1}\)H NMR (400 MHz, CDCl\({}_{3}\)) \(\delta\)(ppm): 6.87 (s, H, Ar-H), 6.03 (s, H, Ar-OH), 4.85 (s, 2H, Ar-CH\({}_{2}\)-Cl), 4.84 (s, 2H, Ar-CH\({}_{2}\)-Cl), 4.68 (s, 2H, Ar-CH\({}_{2}\)-Cl), 3.93 (s, 3H, Ar-OCH\({}_{3}\)). \({}^{13}\)C-NMR (600 MHz, CDCl\({}_{3}\)) \(\delta\)(ppm): 146.8 (C-Ar) 145.1 (C-Ar), 128.9 (C-Ar), 128.7 (C-Ar), 123.4 (C-Ar), 112.9 (C-Ar), 56.3 (OCH\({}_{3}\)), 43.9 (CH\({}_{2}\)); 38.7 (CH\({}_{2}\)), 36.5 (CH\({}_{2}\)). EA found: C 44.65%, H 3.95%; calcd for (C10H11O2 Cl3): C 44.56%, H 4.11%. Mp n.d. (decomposed). 2,6-Bis (chloromethyl)-4-methylphenol (**2f**). Following the general procedure, _p_-cresol (**1f**, 10 mmol) was stirred with PF (22 mmol), conc. HCl (37%, 5.4 mL), and DCM (0.5 mL) at 40 \({}^{\circ}\)C for 6 h. After extraction with DCM, the product was obtained as a white waxy solid, in 76% yield. \({}^{1}\)H NMR (600 MHz, CDCl\({}_{3}\)) \(\delta\)(ppm): 7.09 (s, 2H, Ar-H), 5.55 (br s, 1H, Ar-OH), 4.66 (s, 4H, Ar-CH\({}_{2}\)-Cl), 2.28 (s, 3H, Ar-CH\({}_{3}\)). \({}^{13}\)C-NMR (400 MHz, CDCl\({}_{3}\)) \(\delta\)(ppm): 36.5 (CH\({}_{2}\)), 56.0 (OCH\({}_{3}\)), 113.3 (C-Ar). EA found: C 52.88%, H 5.07%; calcd for (C\({}_{9}\)H\({}_{10}\)OCl\({}_{2}\)): C 52.71%, H 4.91%. Mp n.d. (decomposed).