鏡像選擇合成呋喃[2,3-b]呋喃結構經由Michael/縮醛化/縮醛化連鎖反應

Abstract

本實驗室成功利用Michael/縮醛化/縮醛化連鎖反應，使用低毒性溶劑及溫和反應條件，建構出連續六環呋喃[2,3-b]呋喃結構衍生物，有四個立體中心，具有適中的產率及良好至優異的鏡像超越值。反應以1,3-茚二酮衍生物(1.5 equiv.)及β-四氫萘酮(1.0 equiv.)於甲苯溶劑下，使用奎寧衍生之方烯胺有機掌性氫鍵催化劑(20 mol%)，反應4小時後，可得到連續六環呋喃[2,3-b]呋喃結構衍生物，產率最高可達86%，鏡像超越值最高可達97%ee，經由再結晶純化可達> 99.5% ee。更多相關研究於本實驗室進行中。Our lab successfully synthesized continuous hexacyclic furo[2,3-b]furan scaffold derivatives with four stereogenic centers via Michael/acetalization/acetalization cascade reations. Reaction starting materials were 1,3-indanedion derivatives (1.5 equiv.) and β-tetralone(1.0 equiv.) which were stirred in toluene and used quinine derived squaramide as hydrogen bond organocatalyst. After reaction lasting for 4 hours, continuous hexacyclic furo[2,3-b]furan scaffold derivatives formed with up to 86% yield and up to 97% ee . The enantiomeric excess could be enhanced to over 99.5% ee by recrystalization. The absolute configurations of the cyclized product was determined by the single crystal X-ray analysis. Further related researches are underway in our lab.