1: 61 percent / borane-methyl sulfide / tetrahydrofuran / 1.) 0 deg C, then r.t., 3 h, 2.) MeOH, r.t., overnight, 3.) HCl/MeOH, reflux, 1 h 2: 90 percent / DCC/HOBt / tetrahydrofuran / 24 h / 4 °C 3: 78 percent / benzoyl peroxide, N-bromosuccinimide / CH2Cl2 / 0.5 h / 0 °C 4: 99 percent / Na2CO3 / methanol; H2O / 1 h / 70 °C 5: 84 percent / triethylamine, DCC / tetrahydrofuran / Ambient temperature 6: 67 percent / trifluoroacetic acid / CH2Cl2 / 0.67 h / 0 °C 7: 75 percent / DCC / CH2Cl2 / 1.) -20 deg C to 0 deg C, 3 h, 2.) 4 deg C, 36 h 8: ethanethiol, AlBr3 / CH2Cl2 / 24 h / Ambient temperature 9: DCC, DMAP, DMAP-TFA / CHCl3 / 16 h / Heating View Scheme

trichlorophosphate T=28°C; Bischler-Napieralski reaction; 0.5 h;