NOE和二维NMR技术在倍半萜化学位移归属中的应用

本文用NOE和二维核磁共振技术-COSY,C-H化学位移相关,C-H远程化学位移相关(COLOC),DEPT对二个倍半萜分子的立体化学结构进行了研究,并对其¹H和¹³C化学位移进行了归属。     

Extensive Studies on the AIEt3／THF-Promoted Diastereoselective Tandem Rearrangement／Reduction of a-Hydroxy （Amino） Heterocyclopropane： An Efficient Approach to 2-Quaternary 1,3-Diheteroatom Units

A facile and highly diastereoselective method for the construction of 2-quaternary 1,3-amino alcohols and 1,3-diols has been developed on the basis of the AlEt3/THF-promoted tandem rearrangement/reductive reaction of α-hydroxy (amino) aziridines (epoxides). The progressive achievement in this article included that both 2-epimers of the units could be constructed from the initially same substrate. Also a stereochemistry assignment we reported previously was corrected.     

First Synthesis of (+)-2,14-Deoxyalatol from -Santonin

IntroductionAlargenumberofthedihydroagarofuransesquiter-penes,isolatedfromCelastraceaeplantshavebeendemonstratedtoexhibitmanyimportantbiologicalac-tivities,suchascytotoxic,1antitumor,2immunosuppres-sive,3insecticided,4anti-HIVactivities,5etc.Therefore,synthesisofthiskindofcompoundshasbeenattractingthegreatinterestoforganicchemists,andsomemethodshavebeenreported.6Theseapproaches,however,areusuallyapplicabletothosecompoundswiththespecialhydroxylgroupnumberand/orspecialhydroxylsubsti-tutionfash…     

8-epi-Liphagal的合成研究

四环杂萜类天然产物Liphagal含有新奇的[6-7-5-6]四环骨架, 是磷酸肌醇3-激酶(PI3K)的有效抑制剂之一, 可以选择性抑制细胞增殖和促进细胞死亡, 在治疗炎症、免疫紊乱、癌症以及心血管疾病中有潜在的医用价值. 从廉价的2,4,5-三甲氧基苯甲醛出发, 通过Wittig反应、Cu催化的环化反应、选择性氢化、分子内Friedel-Crafts反应, 以直线步骤最长7步, 8.72%的总收率实现了8-epi-Liphagal高级中间体10的合成.     

(±)-γ-Lycorane的立体选择性合成

高效地合成了 (± ) γ Lycorane。合成中的关键步骤是钯催化分子内的α 芳基化反应。     

抗HIV活性海洋天然产物Didemnaketals的合成研究--C1～C7片段的合成

以天然( )-长叶薄荷酮为原料,通过分子内手性诱导,立体选择性地合成了具有抗艾滋病活性的化合物Didemnaketal A的C1～C7片段,(3R,4S,6R)-3,4-二(叔丁基二甲基硅氧基)-7-羟基-6-甲基-2-庚酮．     

Diastereoselective Synthesis of Chiral Pyrrolidine and Piperidine Ring Systems

A diastereoselective method for the synthesis of chiral pyrrolidine and piperidine ring containing compounds was described. The protocol of bromination followed by aminocyclization furnishes an easily handled while highly efficient procedure for the intramolecular amidation of an isolated double bond. High diastereomeric excess was observed in this synthetic procedure.     

灯油藤中新倍半萜的研究

已知杀虫植物苦皮藤(Celastrus angulatus)中的一些β-二氢沉香呋喃型倍半萜表现出明显的昆虫拒食活性~[1].为进一步研究这类化合物结构与杀虫活性的关系,从而为寻找新的杀虫植物提供依据,我们对灯油藤(C.paniculatus)中的类似化合物进行了研究,从中分离出3种微量成分(1～3).初步生物活性试验表明,化合物3对粘虫(M.separata)表现出明显的拒食活性,拒食率为67％.本文报道这3种化合物的结构.     

手性铝试剂促进的β-环氧醇动力学拆分研究

首次以手性联萘酚修饰的三乙基铝为催化剂对消旋的β-环氧醇的动力学拆分进行了研究, 初步研究结果表明其回收原料的ee值可达60%. 同时研究了不同条件下三乙基铝与手性配体形成的手性路易斯酸对β-环氧醇的动力学拆分的影响, 并探讨了在三乙基铝催化下的反应机理.     

First Synthesis of （＋）-2,14-Deoxyalatol from α-Santonin

A novel and general approach for synthesis of the multi-oxygenated dihydrofuran sesquiterpenes has been developed starting from santonin. The key steps involve: the strategic acid-catalyzed double-bond shifting affording 4, the novel base-promoted epoxide rearrangement of 5 generating two key functionals (the C5-OH and the Δ^7,11 double bond), and the stereoselective cyclization of tetrahydrofuran ring without pre-controlling the stereochemistry of C-7. As an example of this approach, synthesis of ( )-2,14-deoxyalatol was described in detail.