Organocatalytic Synthesis of Tricyclic Chroman Scaffold via 1,6-/Acetalization/1,4- Reaction Sequence

• Main Authors: Chao, Tzu-Ching, 趙姿晴
• Other Authors: Chen, Kwun-Min
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/998pgc

碩士 === 國立臺灣師範大學 === 化學系 === 106 === An organic base catalyzed 1,6-/acetalization/1,4- cascade reaction between 1-(2'-hydroxyphenyl)butane-1,3-dione with many reactive sites and conjugated dien with strong electron withdrawing group leads to the formation of synthetically important tricyclic chromanes scaffolds bearing five stereogenic centers. However, the diastereoselectivities not well（1.6:1 dr）. After that, with methyl vinyl ketone as electrophile reagent to 1,4-addition can improving diastereoselectivities（9:1 dr）in good yield（89%）and including two tetrasubstituted carbon stereogenic centers. This reaction was also put into the process of one pot directly from conjugated dien, 1-(2'-hydroxyphenyl)butane-1,3-dione and methyl vinyl ketone through efficient 1,6-/acetalization/1,4-/1,4- cascade reaction in well yield（74%）and maintain the diastereoselectivities（9:1 dr）. Nevertheless, the enantioselectivity of product is still in study.