A new development to the synthesis of biologically active natural product by the electrocyclic reaction of aza 6π-electron system

（1）具有神经细胞保护活性的多功能化咔唑生物碱的合成研究建立了外消旋和手性藜芦烯基卡奎司他丁的合成方法。通过联烯介导的吲哚2，3-键的电环化反应合成了一个合适的1，3-二氧代3-甲基咔唑。以1-羟基咔唑为原料，在脂肪酶催化下进行不对称乙酰化反应，分别得到手性乙酸酯和手性醇，合成了1-（2-羟基丙基）咔唑。水解手性乙酸酯得到另一种手性醇。用改进的Moscher方法确定了（+）-和（-）-醇的绝对立体化学分别为S-和R-构型。（R）-（-）-乙酸酯经硒酐氧化制得（R）-（-）-去烯基卡奎司他丁。以类似的方式，也从外消旋乙酸酯获得外消旋的异戊二烯基卡奎司他丁。(To出版）。（2）具有两种结构的五环美丝菌素A和B的合成研究 ...更多信息 抗疟和抗肿瘤活性实现了一种新的Calothrixin B的全合成。通过联烯介导的吲哚2，3-键的电环化反应合成了合适的2-（2-硝基苯基）-4-甲氧基甲氧基-3-甲基咔唑。3-甲基咔唑衍生物经DDQ氧化后，甲氧基甲基沿着断裂，得到3-甲酰基咔唑。用Pd-C和H^2还原苯环上的硝基，得到五环吲哚菲啶，再用CAN氧化，得到calothrixin E。(To出版）。（3）5-甲基吲哚-4，7-醌和维谷胺的合成研究完成了5-甲基吲哚-4，7-醌的全合成。通过联烯介导的吡咯2，3-键的电环化反应合成了一种合适的吲哚骨架化合物N-苄基-4-甲氧基-5-甲基吲哚-2-羧酸。经七步反应得到预期产物5-甲基吲哚-4，7-醌。然而，该化合物的数据与福山组报道的天然产物的数据不一致。此外，还以类似的方法合成了6-甲基吲哚-4，7-醌。(To出版）。尝试了用丙二烯介导的电环化反应合成维鲁塔明。可以合成合适的吲哚骨架。将吲哚骨架转化为三环吲哚并亚氨基醌环目前正在研究中。少

(1)Synthetic studies of poly-functionalized carbazole alkaloid possessing neuronal cell protecting activitySyntheses of racemic and chiral desprenylcarquinostatin have been established. A suitable 1,3-dioxygenated 3-methylcarbazole was prepared by the allene-mediated electrocyclic reaction involving the indole 2,3-bond. The 1-(2-hydroxyprpyl)carbazole was synthesized from 1-hydroxycarbazole was subjected to the lipase-catalyzed enantioselective acetylation to give the chiral acetate and the alcohol, respectively. Hydrolysis of the chiral acetate gave the another chiral alcohol. Absolute stereochemistries of (+)- and (-)-alcohols were determined as S- and R- configurations, respectively, by the modified Moscher method. The (R)-(-)-acetate was oxidized by selenic anhydride to produce (R)-(-)- despenylcarquinostatin. Racemic desprenylcarquinostatin was also obtained from racemic acetate in a simila way. (To be published.)(2)Synthetic studies of pentacyclic calothrixins A and B possessing … More antimalarial and antitumor activitiesA new total synthesis of calothrixin B was achieved. A suitable 2-(2-nitrophenyl)-4-methoxymethyloxy-3-methylcarbazole was synthesized by the allene-mediated electrocyclic reaction involving the indole 2,3-bond. Oxidation of 3-methylcarbazole derivative with DDQ gave the 3-formylcarbazole along with the cleavage of methoxymethyl group. Reduction of nitro group on the phenyl ring with Pd-C and H^2 produced the pentacyclic indolophenanthridine, which was oxidized by CAN to provide calothrixin E. (To be published.)(3)Synthetic studies of 5-methylindole-4,7-quinone and veiutamineA total synthesis of 5-methylindole-4,7-quinone was completed. A suitable indole framework, N-benzyl-4-methoxy-5-methylindole-2-carboxylic acid, was synthesized by-the allene-mediated electrocyclic reaction involving the pyrrole 2,3-bond. The expected 5-methylindole-4,7-quinone was obtained in seven steps. However, The data of this compound was not identical with those of natural product reported by Fukuyama group. (Published) Furthermore, 6-methylindole-4,7-quinone was also synthesized in a similar methodology. (To be published.)A synthesis of veiutamine was attempted by the allene-mediated electrocyclic reaction. An appropriate indole framework could be synthesized. Conversion of indole framework into a tricyclic indoloiminoquinone ring is now under investigation. Less