1: N-(tert-butoxycarbonyl)-2-ethoxy-1,2,3,4-tetrahydroquinoline With titanium tetrachloride in dichloromethane T=-30°C; activation; Cyclization; 0.166667 h; 2: 2-(trimethylsilyloxy)-1,3-butadiene in dichloromethane T=20°C; 0.5 h;