1: diethyl 2-allyl-malonate With sodium hydride in tetrahydrofuran T=20°C; 1 h; 2: diethyl 4-bromo-2-butyn-1-yl-propargyl-malonate in tetrahydrofuran T=20°C; 3 h;

1.1: NaH / tetrahydrofuran; various solvent(s) / 1 h / 22 °C 1.2: 79 percent / tetrahydrofuran; various solvent(s) / 2 h / 22 °C 2.1: NaH / tetrahydrofuran; various solvent(s) / 1 h / 20 °C 2.2: 85 percent / tetrahydrofuran; various solvent(s) / 3 h / 20 °C View Scheme