in tetrahydrofuran T=-78 - 20°C;

1: 95 percent / 3-chloroperbenzoic acid / CH2Cl2 / 10 h / 0 °C View Scheme

in tetrahydrofuran 1) -78 deg C 2) -30 deg C, 1-2h;

Yield given. Multistep reaction;

1: trimethyl-oxo-sulfonium iodide With sodium hydride in dimethyl sulfoxide 0.5 h; Inert atmosphere; 2: ethyl 2-ethoxycarbonyl-3-dimethyl(phenyl)silyl-2-propenoate in dimethyl sulfoxide T=20°C; 0.5 h; Inert atmosphere;