1: 3-(5-methyl-2-furanyl)-1-propanol With sulfur trioxide pyridine complex; triethylamine in dimethyl sulfoxide T=0°C; 1 h; 2: carbon tetrabromide With triethylamine; triphenylphosphine in dichloromethane T=-20 - 20°C; 3: With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.166667 h; Further stages.;