tetrakis(triphenylphosphine) palladium(0); sodium formate in N,N-dimethyl-formamide T=100°C; 2 h;

sodium metaborate; dihydrogen peroxide in acetic acid T=80°C; 5 h;

1: 95 percent / 90percent H2O2, maleic anhydride / CH2Cl2 / 1.) room temperature, overnight; 2.) reflux, 4 h 2: 94 percent / tetrakis(triphenylphosphine)palladium, sodium formate / dimethylformamide / 2 h / 100 °C View Scheme

T=120 - 130°C; 1 h;

1: 40 percent / 1 h / 120 - 130 °C 2: 91 percent / 20percent HCl / 5 h / Ambient temperature View Scheme