本論文利用由樟腦磺酸衍生之γ-胺基硫醇化合物(-)-MITH(19)為掌性配位基,應用在烷基鋅對醛類之不對稱加成反應,建立具有光學活性之二級醇。 以二甲基鋅為親核試劑,利用0.5 mol %掌性配位基(-)-MITH(19),在室溫且不添加其他溶劑的條件之下,而使用二甲基鋅之庫存液作為溶劑,進行對醛類的不對稱加成反應,得到之二級醇產物的產率為59-95%,鏡像選擇性最高可達94% ee。 以二乙基鋅為親核試劑,進行對醛類之加成反應,則可以在0.1 mol % (-)-MITH(19)的催化量下,同樣以二乙基鋅庫存液作為溶劑,在0 oC下反應形成的二級醇,其產率為77-96%,而鏡像選擇性介於71-99% ee之間。
Chiral secondary alcohols are ubiquitous synthetic building blocks for important natural products and bioactive compounds. The enantioselective addition of organozinc to aldehydes to construct chiral secondary alcohols attracts numerous interest. This work presents the finding on employment of 0.5 mol % of (-)-2-exo-morpholinoisobor- nane-10-thiol ((-)-MITH) (19) for the addition of Me2Zn to aldehydes, giving up to 94% ee at room temperature. Furthermore, when addition of Et2Zn to aldehydes was conducted at 0 oC in the presence of 0.1 mol % (-)-MITH (19), secondary alcohols was obtained in excellent enantioselectivities(71-99% ee).