1: With lithium aluminium tetrahydride in tetrahydrofuran T=0 - 20°C; 1 h; 2: With hydrogenchloride in tetrahydrofuran; water Product distribution / selectivity;

1: 3,4-dihydro-6-methyl-4-phenyl-2H-benzopyran-2-one With diisobutylaluminium hydride in toluene T=-25°C; 5 h; 2: With citric acid in water; ethyl acetate; toluene T=20°C; 3: diisopropylamine With hydrogen; 5-palladium/activated carbon in methanol T=48°C; P=3800.26 Torr; 12 h;

1: With sodium hydroxide; hydrogen; [RhCl(η2:η2-cycloocta-1,5-diene)]2 in methanol T=50°C; P=9000.9 Torr; 24 h; 2: With toluene-4-sulfonic acid in toluene 4 h; Heating; 3: With diisobutylaluminium hydride in toluene T=-25°C; 5 h; Further stages. Title compound not separated from byproducts.;

1: S,S-chiraphos; NaOH; H2 / [Rh(COD)Cl]2 / methanol / 24 h / 50 °C / 9000.9 Torr 2: DIBALH / toluene / 5 h / -25 °C View Scheme

FeCl3·6H2O in dichloromethane Friedel-Crafts Alkylation; 24 h; Reflux;

diisobutylaluminium hydride in toluene T=-25°C; 5 h;

1: sodium tetrahydroborate / methanol / 1 h / 20 °C 2: FeCl3·6H2O / dichloromethane / 24 h / |Reflux View Scheme

1.1: sodium hydroxide / dichloromethane; water / 1 h / 40 °C 2.1: triethylamine / water / 2 h / 0 °C 3.1: acetonitrile / 12 h / |Reflux 4.1: sodium hydroxide / methanol; water / 4 h / |Reflux 4.2: 1 h / 20 °C 5.1: sodium hydroxide; sodium carbonate / dichloromethane; water / 1 h / 20 °C 5.2: 1 h / |Reflux View Scheme