triphenyl phosphite; chlorine; triethylamine in dichloromethane 2 h; Heating;

1: 1.) boron trifluoride etherate / 1.) THF, 0 deg C; 0 deg C to RT, 70 min; 2.) THF, RT, 14 h 2: 1.) LAH; 2.) NaOH, water / tetrahydrofuran / 1.) 0 deg C to RT, 3.5 h; 2.) RT, 20 min 3: 91 percent / triphenylphosphine, imidazole, iodine / diethyl ether; acetonitrile / 14 h / Ambient temperature 4: 93 percent / dimethylsulfoxide / 2 h / 8 °C 5: 79 percent / n-butyllithium / tetrahydrofuran; hexane / 1.5 h / 0 °C 6: 84 percent / glacial acetic acid, triphenylphosphine / toluene / 48 h / Heating 7: 88 percent / SN<N(TMS)2>2 / hexane / 12 h / Ambient temperature View Scheme

chromium dichloride in tetrahydrofuran; N,N,N',N',N'',N''-hexamethylphosphoric triamide T=40°C; 4 h;

sodium hydroxide

toluene-4-sulfonic acid in benzene 12 h; Heating;

sodium tert-pentoxide; toluene

sodium hydroxide in ethanol T=20°C; 72 h;

piperidine in ethanol 1 h; Ambient temperature;

alanine racemase Y265A; pyridoxal 5'-phosphate T=50°C; Aldol condensation; pH=9.5; 24 h; aq. bufferEnzymatic reaction; optical yield given as percent eeenantioselective reaction;

1: m-chloroperoxybenzoic acid / CH2Cl2 / 18 h / Heating 2: potassium hydroxide / methanol; H2O 3: 4.7 g / ethyldiisopropylamine / CH2Cl2 / 0 - 20 °C View Scheme