N-ethyl-N,N-diisopropylamine in tetrahydrofuran T=5°C; 1.25 h;

1: 1.) conc. hydrochloric acid, sodium nitrite, 2.) stannous chloride, hydrochloric acid / 1.) 5-10 deg C, 1 h, 2.) room temperature, 45 min 2: 78 percent / ethyldiisopropylamine / tetrahydrofuran / 1.25 h / 5 °C View Scheme

maleic anhydride; dihydrogen peroxide in dichloromethane 2 h; Heating;