1: 2-ethoxycarbonyl-2-(2-propynyl)malonic acid diethyl ester With sodium ethanolate in tetrahydrofuran 1.5 h; 2: (E)-4-methylpent-2-enyl methanesulfonate in tetrahydrofuran T=20°C; 5 h;

1: 2-ethoxycarbonyl-2-(2-propynyl)malonic acid diethyl ester With sodium ethanolate in tetrahydrofuran T=20°C; 1.5 h; 2: (E)-4-methylpent-2-enyl methanesulfonate in tetrahydrofuran T=20°C; 3 h; Further stages.;