路易士酸輔佐之分子內環化反應:（E）-5-含鹵亞甲基雙環[2.2.2]辛-2-烯衍生物的簡易合成

Abstract

本文主要分成兩個部份探討路易士酸 (Lewis acids) 輔佐環形2,6-烯炔-1-醇化合物和具第三丁基二甲基矽保護之環形2,6-烯炔-1-醇化合物，經由分子內環化反應，可得到橋形雙環的含鹵素環化產物。第一部份以三氯化鐵作為路易士酸和氯離子來源，輔佐4-(3-芳香基丙炔基)環己-2-烯-1-醇化合物。在室溫，空氣下，在短時間內，進行分子內環化反應，可得到高產率、高立體選擇性的（E）-5-含氯亞甲基雙環[2.2.2]辛-2-烯衍生物。第二部份以三氟化硼乙醚作為路易士酸及氟陰離子來源，輔佐具第三丁基二甲基矽保護之4-(3-芳香基丙炔基)環己-2-烯-1-醇化合物。在室溫、氮氣下，一分鐘進行分子內環化反應，亦可得到高產率、高立體選擇性的（E）-5-含氟亞甲基雙環[2.2.2]辛-2-烯衍生物。

This thesis focuses on Lewis acid-promoted carbohalogenation of 4-(3-arylprop-2-ynyl)cyclohex-2-en-1-ols and TBS-protected cyclic 2,6-enynols afforded the exo-methylene bridged bicycles in good yields. First, FeCl3-promoted carbohalogenation of 4-(3-arylprop-2-ynyl)cyclohex-2-en-1-ols in the air at room temperature produced (E)-5-aryl(chloro)methylene-bicyclo[2.2.2]oct-2-enes in minutes in a stereoselective fashion and in good yields. In this process, FeCl3 acts as both the activating group and the chloride source. Second, BF3•OEt2-promoted carbohalogenation of tert-butyldimetylsilyl-protected 4-(3-arylprop-2-ynyl)cyclohex-2-en-1-ols at room temperature under an atmosphere of nitrogen provided good yields of (E)-5-(fluoro(aryl)methylene)bicyclo[2.2.2]oct-2-enes in one minute and in good stereoselectivities.