單體非重複之寡聯芳香環與四取代呋喃化合物

Furan-Containing Oligoaryls without Repetitive Units and Tetrasubstituted Furans

陳嘉弘(Jia-Hong Chen)

指導教授 ： 陸天堯

國立臺灣大學/理學院/化學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.00157

摘要

炔丙基硫縮酮經有機金屬試劑進行親硫性開環，與醛類化合物反應產生丙二烯醇中間體，於酸性條件下進行分子內環化反應，可生成呋喃與苯環交錯之寡聯芳香環化合物。利用一系列官能基化的炔丙基硫縮酮進行此一鍋式呋喃稠合反應，產生相對應之寡聯芳香環化合物，可進一步利用官能基轉換，應用於苯環兩端向外延伸的分子線之合成。值得注意的是當有酯基存在時，炔丙基硫縮酮仍可作為碳硫鍵之極性逆轉體。應用會集式合成策略，改變苯環兩端向外延伸的方法，可使分子線長度的延伸得以倍數增長。藉由此合成手法，改變單體炔丙基上的取代基，可合成出單體非重複之共軛奈米分子線。
除了藉由三氟醋酸來推動丙二烯醇中間體的合環反應外，醋酸汞亦能夠提供新的反應途徑合成呋喃化合物。其呋喃環上的汞則能夠以一鍋化的方式置換成碘，藉此製備出一系列含碘之呋喃化合物。酯基、烷基、芳香基……等官能基皆能在這樣的反應條件下存在而不分解。結合不同類型的耦合反應，可藉此合成出具位向選擇性的四取代呋喃化合物。

關鍵字

呋喃 ； 三氟醋酸 ； 炔丙基硫縮酮

並列摘要

A new one-pot furan annulation from corresponding propargylic dithioacetals and aldehydes has been reported recently. The bidirectional growth approach was also employed to the one-pot furan annulation for the synthesis of higher homologues towards molecular wires. It is noticeable that propargylic dithioacetal moiety could still serve as carbon-sulfur bond umpolung even in the presence of an ester group. The iterative divergent/convergent doubling approach provide an efficient strategy for the synthesis of benzene/furan alternating oligoaryls by utilizing our one-pot furan annulation reaction. The substituents on the furan rings can be easily varied by changing the substituents in the starting propargylic dithioacetals. This route provides a useful procedure for the synthesis of alternating benzene/furan oligomers without repetitive units.
A convenient procedure for highly regioselective synthesis of tetrasubstituted furans from the corresponding propargylic dithioacetals is described. Treatment of propargylic dithioacetals with n-BuLi and an aldehyde followed by mercuric acetate-promoted annulation and desulfurization affords the corresponding mercurio-substituted furans. Subsequent replacement of the mercuric moiety with iodine and potassium iodide yield the corresponding 2,4,5-trisubstituted-3-iodofurans. It is noteworthy that although these reactions are multistage, it can be accomplished in one pot. Transition-metal catalyzed cross-coupling reactions of the iodofurans furnish a variety of fully substituted furans.

並列關鍵字

Furan ； TFA ； Propargylic dithioacetal

參考文獻

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