Expedient Introduction of β-Methoxyacrylate Unit onto 3-Substituted Indoles and Application of the Resulting Indole-Dienes in Organocascade toward Indolino-Polycyclics
An efficient methodology for introducing a β-alkoxy acrylate unit onto the indolic C-2 position of 3-substitutedindoles has been realized by oxidative radical alkylation of indoles with a xanthate bearing dialkyl acetal functionality and subsequent elimination of alcohol by treatment with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The indole-dienes thus prepared are quite stable and can be stored at
Sequential Electrophilic Trifluoromethanesulfanylation–Cyclization of Tryptamine Derivatives: Synthesis of C(3)-Trifluoromethanesulfanylated Hexahydropyrrolo[2,3-<i>b</i>]indoles
作者:Yi Yang、Xueliang Jiang、Feng-Ling Qing
DOI:10.1021/jo3013385
日期:2012.9.7
A practical and efficient synthesis of C(3)-trifluoromethanesulfanylated hexahydropyrrolo[2,3-b]indoles 5 from tryptamine derivatives was described. The features of this synthesis included electrophilic activation of C(3) of tryptamine derivatives with “CF3S+” and cascade ring cyclization by carbamate nucleophile attacking at C(2). Surprisingly, when Lewis acid (BF3·OEt2) was used as activator instead
实用和有效的合成C(3)-三氟甲烷磺酰化六氢吡咯并[2,3- b ]吲哚5从色胺衍生物。该合成的特征包括对带有“ CF 3 S + ”的色胺胺衍生物的C(3)进行亲电活化,并通过攻击C(2)的氨基甲酸酯亲核试剂实现级联环环化。出乎意料的是,当使用路易斯酸(BF 3 ·OEt 2)代替质子酸(TsOH·H 2 O)进行色胺胺衍生物的亲电子三氟甲烷磺酰化反应时,未环化产物6是优先组建的。此顺序的三氟甲烷磺酰化-环化方案用于合成几种吡咯烷基吲哚类生物碱类似物。评估了这些三氟甲烷磺酰化生物碱类似物对三种癌细胞系(K562,HeLa,L929)的细胞毒性活性。
Catalytic asymmetric construction of C2-symmetric contiguous quaternary carbon centers enabled a concise synthesis of (−)-chimonanthidine and (−)-folicanthine
Herein, we disclose a catalytic asymmetric conjugatedaddition of 3-substutited oxindoles to indol-2-one in situ generated from 3-bromooxindoles promoted by Ni(BF4)2·6H2O/chiral N,N′-chiral dioxide. This protocol enables forging C2-symmetric CQCCs in excellent enantioselectivities as single diastereoisomer via directly fusing two congested 3-substituted oxindoles. The asymmetric synthesis of (−)-chimonanthidine