1: 100 percent / Et3N / benzene / 0.5 h / 0 °C 2: Me3Al/AlCl3 / benzene; tetrahydrofuran; toluene / 2 h / Ambient temperature 3: H2O, SiO2 4: 55 percent / benzene / 0 °C / Irradiation 5: TFA / CH2Cl2 / 1 h / 0 °C View Scheme

Multi-step reaction with 2 steps 1: LDA, DMPU / tetrahydrofuran / 1.) -78 deg C, 10 min, 2.) -78 deg C, 5 h2: AcOH, NaOAc, H2O / diethyl ether / 1 h  

Multi-step reaction with 2 steps 1: 1.) tosyl chloride, pyridine 2.) lithium bromide, acetone2: lithium diisopropyl amide, N,N'-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone / tetrahydrofuran / -78 - -60 °C