1: 100 percent / KOH / ethanol / 3 h / 20 °C 2: 94 percent / pivalaldehyde; O2 / Co(III)-Me2opba / acetonitrile / 20 °C View Scheme

1: (+/-)-2,2-dimethyl-5-phenyl-1,3-dioxolan-4-one With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-78°C; 0.5 h; 2: 4-bromo-benzyl bromide in tetrahydrofuran; hexane T=-78 - 20°C; 4 h;

1.1: 65 percent / H2SO4 / toluene / 24 h / 20 °C 2.1: n-BuLi; iPr2NH / hexane; tetrahydrofuran / 0.5 h / -78 °C 2.2: 75 percent / hexane; tetrahydrofuran / 4 h / -78 - 20 °C View Scheme