1: 4-pent-4-enyl-4-vinyl-oxazolidin-2-one With n-butyllithium in tetrahydrofuran T=-78°C; 2: n-pentylcarbonyl chloride in tetrahydrofuran

1.1: 95 percent / BuLi / hexane; tetrahydrofuran / -78 - 20 °C 2.1: DIBAL-H / CH2Cl2 / 1 h / -100 °C 2.2: 76 percent / 2,6-lutidine / CH2Cl2 / 0.33 h / -100 °C View Scheme