【作者】 王民；

【导师】 涂永强；

【作者基本信息】 兰州大学 ， 有机化学， 2007， 博士

【摘要】 季碳广泛存在于具有重要生物活性的天然产物及其它重要的有机分子中，它的对映选择性合成是有机化学中具有挑战性的研究内容之一。本论文针对这一课题实现了两类手性季碳中心的构筑，并应用于具有新颖结构和良好活性的天然产物全合成研究中。本论文主要包括以下三个方面的内容：一．发展的Quinine／Selectfluor体系可以有效地促进烯丙醇的手性重排反应。首先对反应条件进行了优化，并研究了一系列底物在最优条件下的重排，以61％—82％的对映选择性得到α-季碳-β-氟代醛。并按Mosher方法确定了具有代表性的化合物的绝对构型，由此提出了该重排反应的机理。二、发现了L-prolinamide／PPTS体系可以催化Ronbinson环化1,3-环己二酮衍生物，实现含季碳且具有多官能团侧链的Wieland-Wiescher酮高对映选择性的合成，为天然产物结构多样性的合成奠定了基础。根据产物的绝对构型，对该反应的机理进行了研究探讨。三、对分子内的失对称反应进行了深入研究，发现L-proline／PPTS体系可以高对映选择性的催化合成多官能团的Hajos-Parrish-Eder-Sauer-Wiechert酮，构筑结构多样性合成所需的结构单元，实现结构新颖、具有良好生物活性的海洋生物碱Sieboldine A和(-)-Lepadiformine母核的构建。在目前的研究结果中，以1,3-环戊二酮为起始原料，通过3步反应以32％的收率和97％的对映选择性实现了共同中间体4-14的合成；该中间体经2步反应以65％的收率得到构建(-)-Lepadiformine C三环骨架的重要前体，全合成工作正在进行中。更多还原

【Abstract】 The quaternary carbon extensively exists in active natural products and other useful organic molecules. It is one of the major important and more challenges to enantioselectively construct this type of synthetic structure in Organic Chemistry. Based on this point of view, two synthetic methods for constructing the chiral quaternary carbon were developed and further applied to the total synthesis of some novel structural and active natural products. The following three parts are mainly included:1. Quinine/Selectfluor complex was designed and used to promote effectively the tadem semipinacol rearrangement of allyl alcohols. The reaction condition was firstly optimized and a series of allyl alcohols were subjected to the reaction. The a-quaternary-(3-fluor aldehydes could be obtained from 61% to 82% ee. Based on the Mosher’ method, the absolute configuration of the typical product was determined. A reaction mechanism was proposed according to the controlling stereochemistry of the product.2. L-prolinamide/PPTS system was developed to catalyze Robinson annulation of 1,3-cyclohexanedione derivatives. Using this system, the functionalized carbon chain of Wieland-Wiescher ketone could be synthesized in high enantioselectivity, which was a useful synthon for structural diversity of total synthesis of natural product. A reaction mechanism was proposed according to the absolute configuration of the product.3. In exploration to the reaction of the intermolecular desymmetric method, the functionlized Hajos-Parrish- Eder-Sauer-Wiechert ketone could be synthesized in high enantioselectivity by L-proline/PPTS system, which was used for synthesis of the core structure of biological significant natural product, Sieboline A and (-)-Lepadiformine. Staring from the 1,3-cyclopentanedione, the key intermediate 4-14 efficiently synthesized through 3 steps in an overall 32% yield with 97% ee. The precursor of the tricycli skeleton of (-)-Lepadiformine C was synthesized through 2 steps in 65% yield by the intermediate above. This work is ongoing in our group.更多还原