1: 2-methyl-furan With n-butyllithium in tetrahydrofuran; hexane T=-50 - 20°C; 3 h; 2: indan-2-one in tetrahydrofuran; hexane T=-30 - 20°C; 16 h; 3: With toluene-4-sulfonic acid in toluene 1 h; Heating / reflux;