tris(1,3-dihydro-2-oxobenzoxazolin-3-yl) phosphine oxide; triethylamine in acetonitrile 6 h; Heating;

S=P(Cl)(2-oxazolone-3-yl)2; triethylamine in acetonitrile

1: 47 percent / conc. HCl / 2 h / Ambient temperature 2: 8 percent / triphenylphosphine, 2,2-dipyridyl disulfide, triethylamine / acetonitrile / 3 h / 0 °C View Scheme

1: 72 percent / HCl / CH2Cl2 / 0 °C 2: 1.) 1-<3-(dimethylamino)propyl>-3-ethylcarbodiimide hydrochloride, 2.) triethylamine / 1.) dichloromethane, RT, 23 h, 2.) 20 min.-2 h View Scheme

1: 1.) trifluoroacetic acid, 2.) aluminium amalgam / 1.) dichloromethane, RT, 30-40 min., 2.) ether, reflux, 20 min.-1 h 2: 72 percent / HCl / CH2Cl2 / 0 °C 3: 1.) 1-<3-(dimethylamino)propyl>-3-ethylcarbodiimide hydrochloride, 2.) triethylamine / 1.) dichloromethane, RT, 23 h, 2.) 20 min.-2 h View Scheme

1: 65 percent / sodium cyanoborohydride / HCl; methanol / 0 °C 2: 50 percent / cc. hydrocloric acid / 2 h / Ambient temperature 3: 8 percent / Mukaiyama-Ohno's reagent, Et3N / 4 h / 0 °C View Scheme