天然物Retrojusticidin B, Justicidin E和Helioxanthin之全合成研究

The Total Synthesis of Retrojusticidin B,Justicidin E and Helioxanthin

高子婷(Tzu-Ting Kao)

指導教授 ： 林俊成 ； 夏克山

國立清華大學/理學院/化學系/博士(2016年)

摘要

本文章內容共分為兩個章節：
第一章是研究在溫和條件下以零價鈀與一價銅連續進行Sonogashira耦合反應與[4+1]及[4+2]連鎖式自由基合環反應，有效率地合成多樣性的環戊[b]萘和苯基[b]芴類衍生物。另外進一步發展以三乙酸錳催化進行一連串的5-exo- dig 和 6-exo/endo自由基合環反應，合成在環戊[b]萘化合物的四號碳上具有矽基、芳香基、酯基、醯胺基、酮基、磷酸酯基和鹵素原子多種衍生物。最後以三乙酸錳催化自由基合環反應為關鍵步驟，合成天然物retrojusticidin B、justicidin E 和helioxanthin；總反應途徑的步驟為4至5步驟，總產率分別為45%、33%及44%。
第二章是研究以碘化銅催化位置受活化之酮基化合物進行分子內合環反應，合成多樣性的2,3,5-三取代基呋喃化合物，且可獲得高產率。此合成方法的優勢是操作簡易、反應條件溫和且能適用於多種官能基，具實用價值。

關鍵字

自由基合環反應 ； 合環反應 ； 木酚素 ； 呋喃

並列摘要

The dissertation is divided into two parts:
Chapter I describes that a mild Pd/Cu-cocatalyzed radical cascade, proceeding via a sequence of Sonogashira coupling followed by [4 + 1] and [4 + 2] cycloadditions, has been developed to rapidly assemble cyclopenta[b]naphthalene and benzo[b]fluorene derivatives. In addition, a convenient and general approach for cyclopenta[b]naphthalene derivatives containing a structurally diverse functional group, including trimethyl silyl, aryl, ester, ketone, secondary/tertiary amide, phosphonate and halogen, at C-4 position has also been successfully developed, wherein Mn(III) plays a critical role to effect the oxidative tandem 5-exo-dig and 6-exo/endo cyclization efficiently. Finally, the total synthesis of natural products retrojusticidin B, justicidin E and helioxanthin, making use of a tandem free radical cyclization process mediated by Mn(OAc)3 as a key operation, has been concisely achieved in four or five steps in an overall yield of 45%, 33% and 44%.
Charpter II describes that an efficient Cu(I)-catalyzed intramolecular cyclization of -activated carbonyl compounds has been developed, leading to 2,3,5-trisubstituted furans in good to high yields. The advantage of this synthetic method lies in its operational simplicity, mild reaction conditions and a wide scope of accessible substrates.

並列關鍵字

free radical cyclization ； annulation ； lignan ； furan

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