有機催化不對稱Aza-麥可/麥可環化加成連鎖反應：控制三個立體中心合成螺環噻唑酮2-四氫吡咯酮衍生物

Abstract

本文使用(Z)-5-亞苄基-2-苯基-4(5H)噻唑酮以及(E)-4-(甲氧基氨基)-4-氧代丁-2-烯酸乙酯作為起始物，利用具有方醯胺架構的奎寧衍生物之掌性催化劑提供氫鍵，以活化此有機催化不對稱合成連鎖反應，進行兩次的麥可加成，反應得到螺環化合物。經過一系列條件的篩選，以甲苯作為溶劑，於-20 oC回復至室溫的條件下，添加5 mol%的催化劑進行反應，獲得具有三個手性中心的螺環噻唑酮衍生物，其產率為63%，鏡像選擇性達87% ee。此為一方便且溫和的反應策略，期望未來能為有機不對稱催化合成發展有所貢獻。

A simple asymmetric synthesis of spiro-thiazolone pyrrolidin-2-one was achieved. Uses (Z)-5-benzylidene-2-phenylthiazol-4(5H)-one and ethyl (E)-4-(methoxyamino)-4-oxobut-2-enoate as the starting material. A quinine derivative with a squaramide structure as the catalyst to activate the organocatalytic asymmetric aza-Michael/Michael cyclization Cascade reaction. After a series of screening conitions, toluene was used as the solvent and 5 mol% of the catalyst was added under -20 oC then return to room temperature. The reaction obtained a spiro-thiazolone pyrrolidin-2-one derivative with three chiral centers, the yield was 63% and the enantioselectivity get 87% ee. This is a convenient reaction under mild conditions, and it is expected that it will contribute to the development of organocatalytic asymmetric synthesis in the future.