water; trifluoroacetic acid T=20°C; Inert atmosphere; optical yield given as percent ee;

1: p-toluenesulfonic acid / benzene / 24 h / Heating 2: aq. NaOH / methanol / 6 h View Scheme

1.1: n-butyl lithium / diethyl ether / -78 - -10 °C 1.2: diethyl ether / 0.5 h / -10 °C 2.1: benzene; methanol; diethyl ether / 0.5 h 3.1: p-toluenesulfonic acid / benzene / 24 h / Heating 4.1: aq. NaOH / methanol / 6 h View Scheme

1: benzene; methanol; diethyl ether / 0.5 h 2: p-toluenesulfonic acid / benzene / 24 h / Heating 3: aq. NaOH / methanol / 6 h View Scheme

triethylamine in acetonitrile T=20°C; 5 h; Reflux;

1: DCCI; DMAP / CH2Cl2 / 20 °C 2: Et3N / acetonitrile / 3 h / Heating View Scheme

triethylamine in acetonitrile 3 h; Heating;

1.1: LiHMDS / tetrahydrofuran 1.2: tetrahydrofuran 2.1: EDCI; HOBt View Scheme

1.1: N'-(3-dimethylaminopropyl)-N-ethylcarbodiimide / dichloromethane / 0.33 h / 20 °C / Inert atmosphere 1.2: 20 °C / Inert atmosphere 2.1: water; trifluoroacetic acid / 20 °C / Inert atmosphere View Scheme

1.1: pyridine / dichloromethane / 0.33 h / 0 °C / Inert atmosphere 1.2: 3 h / 0 - 20 °C / Inert atmosphere 2.1: 5 h / Inert atmosphere; Reflux 3.1: toluene-4-sulfonic acid; trimethyl orthoformate / 5 h / 20 °C / Inert atmosphere 4.1: water; sodium hydroxide / 20 °C 5.1: N'-(3-dimethylaminopropyl)-N-ethylcarbodiimide / dichloromethane / 0.33 h / 20 °C / Inert atmosphere 5.2: 20 °C / Inert atmosphere 6.1: water; trifluoroacetic acid / 20 °C / Inert atmosphere View Scheme