1.1: Et3N / diethyl ether / 2 h / 20 °C 2.1: EtMgBr / diethyl ether / 0.5 h / Heating 2.2: diethyl ether / 2 h / Heating View Scheme

1: (prop-2-yn-1-ylselanyl)benzene With ethylmagnesium bromide in diethyl ether 0.5 h; Heating; 2: orthoformic acid triethyl ester in diethyl ether 2 h; Heating;