1: ethyl acetoacetate With n-butyllithium; sodium hydride in tetrahydrofuran; hexane T=-50°C; 0.5 h; 2: I(CH2)2OPMB in tetrahydrofuran; hexane Weiler alkylaion;

1.1: 97 percent / PPh3; imidazole; I2 / tetrahydrofuran / 1 h / 0 - 23 °C 2.1: NaH; nBuLi / tetrahydrofuran; hexane / 0.5 h / -50 °C 2.2: 95 percent / tetrahydrofuran; hexane View Scheme