Diastereoselective Synthesis of Dihydropyrans via Prins Cyclization of Enol Ethers: Total Asymmetric Synthesis of (+)-Civet Cat Compound

Trimethylsilyl trifluoromethanesulfonate (TMSOTf) can be efficiently used for Prins cyclization of acrylyl enol ethers to 5,6-dihydro-2H-pyran-2-acetates stereo- and regioselectively in good yields. The methodology was used for the total synthesis of natural product (+)-civet.