CH3 CH3 CH3-C-O-CH3 浓H2SO4 △ CH3-C-CH2 CH3OH CH3 保护基（Protecting group) CH3 CH3 BrCHaCH CH2OH +CHsC-CH2 BSO BrCH2CH2CH2O-C-CH3 CH3 Mg CH3 DCH2CH2CH2O-C-CH3 醚 △ CH3 CH3 DCH2CH2CH2OH CH3-G-CH2CH3 CH3 CH3 C O CH3 浓H2 SO4 BrCH2CH2CH2OH + CH3 C CH3 CH2 保护基（Protecting group） H2 SO4 DCH2 CH2 CH2OH + CH3-C CH2 CH3 BrCH2CH2CH2O C CH3 CH3 CH3 H2 SO4 Mg 醚 D2 O CH3 CH3 CH3 DCH2CH2CH2O C CH3 C CH3 CH2 + CH3 OH