經由不對稱連鎖1,6-加成/1,4-氧麥可加成反應合成四取代4H-吡喃化合物

Abstract

有機催化不對稱連鎖反應，具簡單操作及符合綠色化學的特色，已成為目前研究的趨勢。透過氧-麥可加成反應可以合成許多具有生物活性的化合物，結合1,6-加成反應與1,4-氧麥可加成反應，進行不對稱合成反應有其挑戰性。本研究使用4-羥基香豆素與1,3-茚二酮雙烯化合物作為起始物，在20 mol%三乙胺的催化下，於60 oC下反應一天，進行1,6-加成/1,4-氧麥可加成鹼催化連鎖反應，得到具有四取代4H-吡喃架構的產物，並測試此反應之官能基容忍度，得到中等產率及優異非鏡像選擇性(> 20:1 d.r.)。The use of organic catalyzed asymmetric domino reaction has become the current research trend, which characteristics are simple operation and corresponding to the principle of green chemistry. Many biologically active compounds can be synthesized through oxa-Michael reaction. Combining with the 1,6-addition reaction and 1,4-oxa Michael reaction to carry out asymmetric synthesis has its challenges.In this study, the reactions were carried out with 4-hydroxycoumarin and 1,3-indenedione compounds as starting materials, under 20 mol% triethylamine to react at 60 oC for one day. Through 1,6-addition and 1,4-oxa Michael reaction base catalyzed domino reaction to obtain a product with tetra-substituted 4H-pyran structure and tested the tolerance of functional group, which obtained moderate yield and excellent diastereoselectivity (> 20 :1 d.r.).