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首页> 外文期刊>Chemistry: A European journal >Diversification of ortho-Fused Cycloocta-2,5-dien-1-one Cores and Eight- to Six-Ring Conversion by sigma Bond C-C Cleavage
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Diversification of ortho-Fused Cycloocta-2,5-dien-1-one Cores and Eight- to Six-Ring Conversion by sigma Bond C-C Cleavage

机译：通过σ键C-C裂解使邻融合的Cycloocta-2,5-dien-1一核和八环到六环转化多样化

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Sequential treatment of 2-C6H4Br(CHO) with LiCCR1 (R-1=SiMe3, tBu), nBuLi, CuBrSMe2 and HCCCHClR2 [R-2=Ph, 4-CF3Ph, 3-CNPh, 4-(MeO2C)Ph] at -50 degrees C leads to formation of an intermediate carbanion (Z)-1,2-C6H4{C-A(=O)CCBR1}{CH=CH(CH-)R-2} (4). Low temperatures (-50 degrees C) favour attack at C-B leading to kinetic formation of 6,8-bicycles containing non-classical C-carbanion enolates (5). Higher temperatures (-10 degrees C to ambient) and electron-deficient R-2 favour retro sigma-bond C-C cleavage regenerating 4, which subsequently closes on C-A providing 6,6-bicyclic alkoxides (6). Computational modelling (CBS-QB3) indicated that both pathways are viable and of similar energies. Reaction of 6 with H+ gave 1,2-dihydronaphthalen-1-ols, or under dehydrating conditions, 2-aryl-1-alkynylnaphthlenes. Enolates 5 react in situ with: H2O, D2O, I-2, allylbromide, S2Me2, CO2 and lead to the expected C-E derivatives (E=H, D, I, allyl, SMe, CO2H) in 49-64% yield directly from intermediate 5. The parents (E=H; R-1=SiMe3, tBu; R-2=Ph) are versatile starting materials for NaBH4 and Grignard C=O additions, desilylation (when R-1=SiMe) and oxime formation. The latter allows formation of 6,9-bicyclics via Beckmann rearrangement. The 6,8-ring iodides are suitable Suzuki precursors for Pd-catalysed C-C coupling (81-87%), whereas the carboxylic acids readily form amides under T3P (R) conditions (71-95%).
机译：在以下位置用LiCCR1（R-1 = SiMe3，tBu），nBuLi，CuBrSMe2和HCCCHClR2 [R-2 = Ph，4-CF3Ph，3-CNPh，4-（MeO2C）Ph]依次处理2-C6H4Br（CHO）- 50摄氏度导致形成中间碳负离子（Z）-1,2-C6H4 {CA（= O）CCBR1} {CH = CH（CH-）R-2}（4）。低温（-50摄氏度）有利于C-B的进攻，导致含有非经典C-碳二烯烯醇化物的5,8-二环的动力学形成（5）。较高的温度（相对于环境温度为-10摄氏度）和缺乏电子的R-2有利于sigma键逆向C-C裂解的再生，该裂解4随后在C-A上闭合，提供6,6-双环醇盐（6）。计算模型（CBS-QB3）表明这两种途径都是可行的，并且具有相似的能量。 6与H +的反应生成1,2-二氢萘-1-醇，或在脱水条件下生成2-芳基-1-炔基萘。烯醇盐5与以下物质原位反应：H2O，D2O，I-2，烯丙基溴，S2Me2，CO2并以49-64％的产率直接得到预期的CE衍生物（E = H，D，I，烯丙基，SMe，CO2H）中间体5。母体（E = H; R-1 = SiMe3，tBu; R-2 = Ph）是用于NaBH4和格利雅德C = O添加，甲硅烷基化（当R-1 = SiMe时）和肟形成的通用原料。后者允许通过贝克曼重排形成6，9-双环。 6,8-环碘化物是用于Pd催化的C-C偶联的合适的Suzuki前体（81-87％），而羧酸在T3P（R）条件下容易形成酰胺（71-95％）。

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