1: 15.09 g / conc. H2SO4 / methanol / 1 h / Ambient temperature 2: 26.79 g / pyridine / 4 h / 0 - 5 °C 3: LAH / diethyl ether / Ambient temperature 4: 19.0 g / pyridine / 3 h / 0 - 5 °C 5: NaI / acetone / 1) 4 h, reflux; 2.) 3 h, RT 6: 1) LDA, HMPA / 1) THF, -69 deg C, 2.75 h; 2) THF, 33 h, -40 deg C View Scheme

Multi-step reaction with 2 steps 1: 15.09 g / conc. H2SO4 / methanol / 1 h / Ambient temperature2: 26.79 g / pyridine / 4 h / 0 - 5 °C  

Multi-step reaction with 5 steps 1: 15.09 g / conc. H2SO4 / methanol / 1 h / Ambient temperature2: 26.79 g / pyridine / 4 h / 0 - 5 °C3: LAH / diethyl ether / Ambient temperature4: 19.0 g / pyridine / 3 h / 0 - 5 °C5: NaI / acetone / 1) 4 h, reflux; 2.) 3 h, RT