Synthesis of (¡À)- and (+)-perovskone

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• 作者：George Majetich  ; ;   ; ^{majetich@chem.uga.edu} ; Yong Zhang ; Xinrong Tian ; Jonathan E. Britton^&dagger ; ; Yang Li^&Dagger ; ; Ryan Phillips
• 关键词：Perovskone ; Cyclialkylation ; Friedel&ndash ; Crafts alkylation ; Cascade reaction ; Pd&ndash ; ¦Ð&ndash ; allyl chemistry and one-pot reaction
• 刊名：Tetrahedron
• 出版年：2011
• 出版时间：30 December 2011
• 年：2011
• 卷：67
• 期：52
• 页码：10129-10146
• 全文大小：2030 K

文摘

A biomimetic synthesis of the triterpene (¡À)-perovskone was achieved featuring a remarkable polycyclization process in which three rings, four bonds, and five stereocenters were created in a single operation in 82 % yield. This convergent synthesis required 16 steps, starting from vanillin, and proceeded in 9 % overall yield. A second route to prepare optically active quinone 2 took 15 steps in 36 % overall yield and featured a palladium-catalyzed reductive allylic transposition to establish the C-5 chirality stereospecifically. Quinone (?-2 was converted to (+)-perovskone (1) via a polycyclization cascade, which created four rings, five bonds, and six stereocenters in a single operation in 50 % yield.