sodium hydroxide in methanol; N,N-dimethyl acetamide; toluene 2 h;

1: NaOMe-d3 With copper(I) bromide in methanol-d4 T=100°C; 2: 4-hydroxy-3-bromo-benzaldehyde in methanol-d4 T=120°C; 1.5 h;

1: 83 percent / K2CO3 / acetone / 41 °C 2: pyridinium toluene-p-sulfonate, EtOH / 3 h / 55 °C 3: 77 percent / KBrO3, HBr / acetic acid / 4 h / Ambient temperature 4: 96 percent / pyridinium toluene-p-sulfonate / CH2Cl2 / 4 h / Ambient temperature 5: 1.) n-BuLi, 2.) HCl, H2O / 1.) THF, hexane, -78 deg C, 45 min; 2 h, 2.) THF, hexane, r.t., 1 h View Scheme

1: 77 percent / KBrO3, HBr / acetic acid / 4 h / Ambient temperature 2: 96 percent / pyridinium toluene-p-sulfonate / CH2Cl2 / 4 h / Ambient temperature 3: 1.) n-BuLi, 2.) HCl, H2O / 1.) THF, hexane, -78 deg C, 45 min; 2 h, 2.) THF, hexane, r.t., 1 h View Scheme

1: 95 percent / pyridinium toluene-p-sulfonate / CH2Cl2 / 3 h / Ambient temperature 2: 83 percent / K2CO3 / acetone / 41 °C 3: pyridinium toluene-p-sulfonate, EtOH / 3 h / 55 °C 4: 77 percent / KBrO3, HBr / acetic acid / 4 h / Ambient temperature 5: 96 percent / pyridinium toluene-p-sulfonate / CH2Cl2 / 4 h / Ambient temperature 6: 1.) n-BuLi, 2.) HCl, H2O / 1.) THF, hexane, -78 deg C, 45 min; 2 h, 2.) THF, hexane, r.t., 1 h View Scheme

hydrogenchloride; n-butyllithium; water 1.) THF, hexane, -78 deg C, 45 min; 2 h, 2.) THF, hexane, r.t., 1 h; Yield given. Multistep reaction;

piperidine; pyridine T=70°C; Knoevenagel reaction; 18 h;