1: With N-ethyl-N,N-diisopropylamine in diethylene glycol dimethyl ether T=160°C; Inverse-electron-demand Diels-Alder reaction; 48 h; Inert atmosphere; 2: in hexane 2.5 h; Inert atmosphereUV-irradiation;

1: With N-ethyl-N,N-diisopropylamine in diethylene glycol dimethyl ether T=160°C; Inverse-electron-demand Diels-Alder reaction; 48 h; Inert atmosphere; 2: in dichloromethane Inert atmosphereUV-irradiation;