【作者】 徐衍；

【导师】 李战雄； 杨军；

【作者基本信息】 苏州大学 ， 纺织化学与染整工程， 2011， 硕士

【摘要】 烯基硼酸可通过偶联反应、Petasis反应等构建碳-碳键,在有机合成中具有广泛的应用价值,由于构型专一的多取代顺式烯基硼酸的合成较为困难,相关文献报道较少,因此其合成方法受到硼化学研究人员的关注。本文通过铜催化下格氏试剂对炔丙醇的碳镁化反应及转金属反应“一锅法”制备了构型专一的二取代烯基硼酸(4-substituted-1,2-oxaborol-2(5H)-ol)等多种顺式烯基硼化物。1.在制备二取代烯基硼酸后,研究了二取代烯基硼酸与NCS的氯代反应。通过模板反应研究了反应温度、反应时间、NCS和碱的用量等条件对氯代反应的影响并筛选得到了最优反应条件,然后进行了相应的底物拓展,制备了一系列的顺式烯基氯化物。通过二维1H-1H NOESY谱对所得烯基氯化合物中双键的构型进行了分析,结果表明双键构型未发生翻转,并通过IR、1H NMR、13C NMR和MS等对各产物进行了结构鉴定。研究结果表明,含有苯基、烷基取代基的烯基硼酸与NCS发生氯代反应后都能以良好的收率得到相应的氯代产物。由此我们建立了通过二取代烯基硼酸与NCS的氯代反应制备相应二取代烯基氯化物的方法,该方法操作简便,反应条件温和,收率较高,且反应构型能够得到保持。2.研究了末端带有取代基的一级炔丙醇的碳镁化反应,通过核磁分析的方法对质子解产物(不含氘)和氘水捕捉碳镁化反应所得活泼的内烷氧基烯基镁中间体(含氘)的比例进行分析,由此探索改进碳镁化反应的收率。在最优条件下末端带有取代基的一级炔丙醇可以良好的反应收率与格氏试剂进行碳镁化反应。在此研究结果上进一步开展了该内烷氧基烯基镁中间体与硼酸酯的转金属反应研究,初步得到了三取代顺式烯基硼酸。由于氘解反应证明内烷氧基烯基镁中间体可以高收率的形成,我们认为中间体内烷氧基烯基镁3位取代基的位阻降低了其与硼酸酯的反应活性。更多还原

【Abstract】 Organoboronic acids are important nuclephiles which undergo Suzuki cross-coupling reaction and Petasis reaction. The synthesis methods of alkenylboronic acids are limited compared to the arylboronic acids. Many chemists focus their research interests on developling new methodologies to synthesize the stereodifined multi-substituted cis-alkenylboronic acid.Based on our previous work, we have focused on the synthesize of (Z)-2,2-disubstituted alkenylboronic acids from the propargyl alcohols by copper-catalyzed carbomagnesiation reaction and subsequent transmetalation reaction. Then the chlorination reaction of (Z)-2,2-disubstituted alkenylboronic acids with NCS was studied. The reaction temperature, reaction time, the equivalent of NCS and base are studied through the template reaction and an optimized condition was obtained, and the structure of the aimed product was identified by FT-IR, 1H NMR, 13C NMR and MS. The configuration of the product was confirmed to be maintained by two-dimensional 1H-1H NOESY spectrum. Several alkenylboronic acids with different function groups substituted were found to be suffered chlorination smoothly with moderate to high yield. As a result, we know that the trans-chloro alkene can be given by the chlorination reaction between (Z)-2,2-disubstituted alkenylboronic acids and NCS with high yield by mild reaction condition, and simple and convenient process.The carbomagnesiation of substituted propargyl alcohols with Grignard reagent was studied. The intermediate was trapped with D2O. Under the optimized condition, the deuterated allylic alcohol was got with good yield. Further more, the transmetallation reaction between the intermediate and boronic esters was researched. Unfortunately, 3,4-Disubstituted-1,2-oxaborol-2(5H)-ols were obtained and indentified in poor yields in this method. In regard to this, the steric effect the R group of substituted propargyl alcohols is proposed to hinder the transmetalation of intermediate with trialkyl borates.更多还原