1.1: AlCl3, aluminium chloride / dichloromethane / 1 h / 0 - 20 °C 2.1: sulfur; morpholine / 12 h / 130 °C 2.2: 12 h / |Reflux 3.1: boron trifluoride diethyl etherate / 0.17 h / 100 °C 3.2: 0.33 h / 55 °C 3.3: 3 h / 80 °C 4.1: acetic acid; hydrogen; platinum on carbon / 12 h / 100 °C 5.1: acetic acid; 3,4,5-trimethoxyphenylboronic acid / toluene / 12 h / |Reflux; |Inert atmosphere 6.1: boron tribromide / dichloromethane / 2 h / -78 - 20 °C View Scheme

1.1: sulfur; morpholine / 12 h / 130 °C 1.2: 12 h / |Reflux 2.1: boron trifluoride diethyl etherate / 0.17 h / 100 °C 2.2: 0.33 h / 55 °C 2.3: 3 h / 80 °C 3.1: acetic acid; hydrogen; 5 palladium on charcoal / ethanol; water / 12 h / 20 °C 4.1: acetic acid; 3,4,5-trimethoxyphenylboronic acid / toluene / 12 h / |Reflux; |Inert atmosphere 5.1: boron tribromide / dichloromethane / 2 h / -78 - 20 °C View Scheme

1.1: sodium hydroxide / water / 3 h / 0 - 70 °C 2.1: AlCl3, aluminium chloride / dichloromethane / 1 h / 0 - 20 °C 3.1: sulfur; morpholine / 12 h / 130 °C 3.2: 12 h / |Reflux 4.1: boron trifluoride diethyl etherate / 0.17 h / 100 °C 4.2: 0.33 h / 55 °C 4.3: 3 h / 80 °C 5.1: acetic acid; hydrogen; platinum on carbon / 12 h / 100 °C 6.1: acetic acid; 3,4,5-trimethoxyphenylboronic acid / toluene / 12 h / |Reflux; |Inert atmosphere 7.1: boron tribromide / dichloromethane / 2 h / -78 - 20 °C View Scheme

1.1: boron trifluoride diethyl etherate / 0.17 h / 100 °C 1.2: 0.33 h / 55 °C 1.3: 3 h / 80 °C 2.1: acetic acid; hydrogen; 5 palladium on charcoal / ethanol; water / 12 h / 20 °C 3.1: acetic acid; 3,4,5-trimethoxyphenylboronic acid / toluene / 12 h / |Reflux; |Inert atmosphere 4.1: boron tribromide / dichloromethane / 2 h / -78 - 20 °C View Scheme

1: acetic acid; hydrogen; 5 palladium on charcoal / ethanol; water / 12 h / 20 °C 2: acetic acid; 3,4,5-trimethoxyphenylboronic acid / toluene / 12 h / |Reflux; |Inert atmosphere 3: boron tribromide / dichloromethane / 2 h / -78 - 20 °C View Scheme

1: acetic acid; 3,4,5-trimethoxyphenylboronic acid / toluene / 12 h / |Reflux; |Inert atmosphere 2: lithium aluminium tetrahydride / diethyl ether / 6 h / |Reflux 3: boron tribromide / dichloromethane / 2 h / -78 - 20 °C View Scheme