1.1: methyllithium / formaldehyde diethyl acetal; tetrahydrofuran / -70 - -60 °C / Inert atmosphere 1.2: 0.5 h / -50 - -40 °C / Inert atmosphere 1.3: -60 - -50 °C / Inert atmosphere 2.1: hydrogen / palladium 10 on activated carbon / ethyl acetate; water / 60 °C / 3000.3 Torr 3.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1 h / -70 - -60 °C 3.2: -70 - 0 °C 4.1: trifluoroacetic acid / acetonitrile / 16 h / 15 - 30 °C 5.1: Lipase PS SD / acetone / 22 h / 50 - 60 °C / pH 8 / Enzymatic reaction View Scheme

1.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 1 h / -10 - 0 °C 1.2: -10 - 0 °C 2.1: methyllithium / formaldehyde diethyl acetal; tetrahydrofuran / -70 - -60 °C / Inert atmosphere 2.2: 0.5 h / -50 - -40 °C / Inert atmosphere 2.3: -60 - -50 °C / Inert atmosphere 3.1: hydrogen / palladium 10 on activated carbon / ethyl acetate; water / 60 °C / 3000.3 Torr 4.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1 h / -70 - -60 °C 4.2: -70 - 0 °C 5.1: sodium hydroxide; sodium dihydrogenphosphate / Lipase PS SD / acetone / 50 °C / pH 7 / Enzymatic reaction 6.1: sulfuric acid / acetonitrile; water / 15 °C View Scheme

1.1: methyllithium / formaldehyde diethyl acetal; tetrahydrofuran / 0.5 h / -70 - -60 °C / Inert atmosphere 1.2: 0.5 h / -50 - -40 °C / Inert atmosphere 1.3: -60 - -50 °C 2.1: hydrogen / palladium 10 on activated carbon / ethyl acetate; water / 60 °C / 3000.3 Torr 3.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1 h / -70 - -60 °C 3.2: -70 - 0 °C 4.1: trifluoroacetic acid / acetonitrile / 16 h / 15 - 30 °C 5.1: Lipase PS SD / acetone / 22 h / 50 - 60 °C / pH 8 / Enzymatic reaction View Scheme

1.1: methyllithium / formaldehyde diethyl acetal; tetrahydrofuran / -70 - -60 °C / Inert atmosphere 1.2: 0.5 h / -50 - -40 °C / Inert atmosphere 1.3: -60 - -50 °C / Inert atmosphere 2.1: hydrogen / palladium 10 on activated carbon / ethyl acetate; water / 60 °C / 3000.3 Torr 3.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1 h / -70 - -60 °C 3.2: -70 - 0 °C 4.1: trifluoroacetic acid / acetonitrile / 16 h / 15 - 30 °C 5.1: Lipase PS SD / acetone / 22 h / 50 - 60 °C / pH 8 / Enzymatic reaction View Scheme

1.1: 2,2'-azo-bisisobutyronitrile / toluene / 80 - 85 °C 2.1: methyllithium / formaldehyde diethyl acetal; tetrahydrofuran / 0.5 h / -70 - -60 °C / Inert atmosphere 2.2: 0.5 h / -50 - -40 °C / Inert atmosphere 2.3: -60 - -50 °C 3.1: hydrogen / palladium 10 on activated carbon / ethyl acetate; water / 60 °C / 3000.3 Torr 4.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1 h / -70 - -60 °C 4.2: -70 - 0 °C 5.1: sodium hydroxide; sodium dihydrogenphosphate / Lipase PS SD / acetone / 50 °C / pH 7 / Enzymatic reaction 6.1: sulfuric acid / acetonitrile; water / 15 °C View Scheme

1.1: hydrogen / palladium 10 on activated carbon / ethyl acetate; water / 60 °C / 3000.3 Torr 2.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1 h / -70 - -60 °C 2.2: -70 - 0 °C 3.1: sodium hydroxide; sodium dihydrogenphosphate / Lipase PS SD / acetone / 50 °C / pH 7 / Enzymatic reaction 4.1: sulfuric acid / acetonitrile; water / 15 °C View Scheme

1.1: hydrogen / palladium 10 on activated carbon / ethyl acetate; water / 60 °C / 3000.3 Torr 2.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1 h / -70 - -60 °C 2.2: -70 - 0 °C 3.1: sodium hydroxide; sodium dihydrogenphosphate / Lipase PS SD / acetone / 50 °C / pH 7 / Enzymatic reaction 4.1: sulfuric acid / acetonitrile; water / 15 °C View Scheme

1: trifluoroacetic acid / acetonitrile / 16 h / 15 - 30 °C 2: Lipase PS SD / acetone / 22 h / 50 - 60 °C / pH 8 / Enzymatic reaction View Scheme

1.1: zinc(II) hydroxide / water; tert-butyl methyl ether / 1 h / Inert atmosphere 1.2: 24 h 2.1: diisobutylaluminium hydride / dichloromethane; toluene / -78 °C 2.2: 1 h / 20 °C 3.1: potassium tert-butylate / tetrahydrofuran / 0.83 h / 0 - 20 °C 3.2: 3 h 4.1: Dess-Martin periodane / dichloromethane / 2 h 5.1: hydrogen / palladium 10 on activated carbon / dichloromethane / 15 h / 103.43 Torr 6.1: tert-butylamine / ethyl acetate / 20 °C 6.2: pH 5 View Scheme

1.1: 1H-imidazole / dichloromethane / 15 h 1.2: 0 °C / pH 3 - 4 2.1: sodium hydride / tetrahydrofuran; mineral oil / 1.5 h / 0 - 20 °C 2.2: 15 h / 0 - 20 °C 3.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 0 °C 4.1: oxalyl dichloride / dichloromethane; dimethyl sulfoxide / 0.75 h / -78 °C 4.2: 0.5 h / -78 °C 5.1: zinc(II) hydroxide / water; tert-butyl methyl ether / 1 h / Inert atmosphere 5.2: 24 h 6.1: diisobutylaluminium hydride / dichloromethane; toluene / -78 °C 6.2: 1 h / 20 °C 7.1: potassium tert-butylate / tetrahydrofuran / 0.83 h / 0 - 20 °C 7.2: 3 h 8.1: Dess-Martin periodane / dichloromethane / 2 h 9.1: hydrogen / palladium 10 on activated carbon / dichloromethane / 15 h / 103.43 Torr 10.1: tert-butylamine / ethyl acetate / 20 °C 10.2: pH 5 View Scheme