Celite; pyridinium chlorochromate in dichloromethane T=20°C; Cooling with ice;

1: 1,2-dibromo-propane With lithium diisopropyl amide in tetrahydrofuran; hexane T=-78 - 0°C; 2: N-methoxy-N-methyl-3-phenyl-propionamide in tetrahydrofuran; hexane T=-78 - 20°C; 3: With hydrogenchloride in tetrahydrofuran; hexane; water T=0°C;

Yield given. Multistep reaction;