dirhodium tetraacetate in toluene T=110°C; 3.5 h;

perfluorobutanesulfonyl azide; triethylamine in dichloromethane T=20°C; 0.25 h;

1: dimethyl methoxycarbonylmethanephosphonate With sodium hydride in tetrahydrofuran; mineral oil T=-78 - 20°C; 1.5 h; Inert atmosphere; 2: 4-Acetylaminobenzenesulfonyl Azide in tetrahydrofuran; mineral oil T=20°C; Inert atmosphere;

in diethyl ether; dichloromethane 1 h;