【作者】 刘凤伟；

【导师】 许新华；

【作者基本信息】 湖南大学 ， 有机化学， 2007， 硕士

【摘要】 炔基碘是一类重要的有机合成中间体,在偶联等反应中应用非常广泛,目前炔基碘的制法存在反应时间长,试剂昂贵,反应条件要求苛刻,操作复杂等中的某些缺点。我们的研究目的是要找到一种条件温和、操作简单、试剂便宜的合成方法。氢氧化铯为无机超强碱,能与弱酸形成稳定的碳负或杂负离子,该负离子具有强的亲核进攻能力,在室温下就能与许多底物进行反应。因此我们设计以氢氧化铯作碱来促进端炔与碘反应制备炔基碘。实验表明以TBAI为相转移催化剂,4?分子筛为吸水剂,在溶剂THF中,氢氧化铯能顺利的促进端炔与碘化合成炔基碘。该法具有反应速率快、操作简单、产率高等特点,是制备炔基碘的一种好方案。但氢氧化铯促进端炔与碘的反应需要等当量的氢氧化铯,由于氢氧化铯的昂贵,限制了该法的进一步应用。为了节省铯离子的用量,我们设计以催化量的碳酸铯与计量的氢氧化钾体系来代替等当量的氢氧化铯。结果发现,室温下以TBAI为相转移催化剂,4?分子筛为吸水剂,在混合溶剂THF-HMPA中,以氢氧化钾作碱,碳酸铯能催化端炔与碘反应得到炔基碘。与前面的方案相比,在反应时间稍延长的基础上,炔基碘基本上能得到满意的产率。该方案达到了节省铯离子的用量的目的。为炔基碘的扩大应用提供了一种新的选择方案。在研究醚的的合成中,我们用中性盐氯化铯来代替碳酸铯,采用催化量的氯化铯与计量的氢氧化钾体系来应用于芳醚的合成。实验发现,在室温下以DMF为溶剂,氢氧化钾作碱,采用一锅法,氯化铯能顺利的催化伯卤代烃与酚的反应,高产率的得到芳香醚。我们进一步采用催化量的氯化铯与计量的氢氧化钾体系来应用于脂肪醚的合成。发现室温下以DMF为溶剂,TBAI为相转移催化剂,4?分子筛为吸水剂,氢氧化钾/氯化铯体系同样能够促进醇(包括不活泼的伯醇和叔醇)与伯卤代烃反应得到相应的脂肪醚。二烷基二硒醚是一类重要的中间体,文献报道了许多制备方法,其中磺酸酯与二硒化钾(钠)的反应,在DMF中需要加热到100℃才能有效进行,这必然限制了那些在高温下不稳定的有机物在该体系中的应用。我们在二硒化钾与磺酸酯反应的体系中加入催化量的碳酸铯,发现室温下利用铯离子带来的二硒二负离子的高亲核性就可促进二硒化钾化与各种对甲苯磺酸酯反应,获得相应的二烷基二硒醚。更多还原

【Abstract】 1-Iodoalkynes are one of the useful intermediates in organic synthesis. For example they are widely used in coupling reactions. By far the methods of synthesis 1-iodoalkynes however exist somewhat disadvantages, such as long reaction time, expensive reagents, harsh reaction conditions, hard to handle and so on. Our research purpose is to design a method that the reagents are cheap, the reactions are in mild conditions, and the work-up is simple. Cesium hydroxide is an inorganic superior base, it can react with weak acids to form the corresponding stable Carbon or hetero anions, which are very strong nucleophiles. They can react smoothly with many reagents at room temperature. So we decide to make terminal alkynes react with iodines by using CsOH as base. The results showed that the employment of CsOH in the presence of TBAI and 4 ? MS makes the iodination of terminal alkynes come true in the solvent of THF. In a short time with good to excellent yields proved this method is a good protocol to form 1-iodoalkynes. However the iodination of terminal alkynes needs equivalent amount of CsOH. Its price limits its further application. Regarding to its economic factor, we design using KOH (2.0eq)/ Cs2CO3(0.2eq) system to take place of quantitative CsOH to develop the iodination of terminal alkynes. The experiments results showed that the employment of KOH (2.0eq)/ Cs2CO3 (0.2eq) system involving the use of TBAI and 4 ? MS in DMF can also make the iodination smoothly accomplished, only need a little longer reaction time. The results of this protocol would promise the 1-iodoalkynes for further application.On the research of ethers synthesis, we use CsCl instead of Cs2CO3 as catalyst for the synthesis of alkyl phenyl ethers. We found at room temperature, taking DMF as solvent, the KOH (2.0eq)/ CsCl(0.2eq) system can make phenols react with both reactive and unreactive primary halide in a one-pot way, with excellent yields of corresponding alkyl phenyl ethers.Further more, we take the KOH (2.0eq)/ CsCl(0.2eq) system for the O-alkylation of alcohols for the alkyl ethers synthesis. This protocol involves the use of TBAI, 4 ? MS in DMF. The experiments result satisfied us: Various substrates including unreactive primary and tertiary alcohols were converted smoothly to the corresponding ethers at room temperature, both the reactive and unreactive primary halides are proper electrophiles.The ethers of diselenides are an important intermediates in organic synthesis. Many methods have been reported in literature. Among them, the tolsylates react with dipotasium(or disodium) disenilide need a high temperature of 100℃. However for those unstable substrates at high temperature are unfit in this system. By the employment of a catalytic amount of cesium carbonate, we found that the tolsylates can smoothly react with dipotasium disenelide at room temperature, with good to excellent yields of corresponding dialkyl disenilides.更多还原