Selective electrophilic cyclization of <i>ortho</i>-carbonylarylacetylenols for the synthesis of cyclopenta[<i>a</i>]naphthalenol and 2-phenylnaphthalen-1-ol analogs
Selective cyclization occurred when the reaction was conducted in methyl trimethylacetate solvent which predominantly produced the 2-phenylnaphthalen-1-ol product through 6-endo-dig cyclization without elimination or the formation of cyclopenta[a]naphthalenol via shutting down the 5-exo-dig mode of cyclization. Switching the acid from a Brønsted acid to Bi(OTf)3 led to smooth reactions, providing
这项工作展示了一种通过选择性环化合成环戊[ a ]萘酚和2-苯基萘-1-醇类似物的新方法。采用邻炔基芳基烯酮作为常见底物,可以通过 2-卤代芳基苯乙酮和 pent-4-yn-1-ol 衍生物之间的 Sonogashira 偶联来制备。这些前体无需纯化即可通过在加热条件下用(+)-CSA处理来构建2-苯基萘-1-醇中间体。当反应在三甲基乙酸甲酯溶剂中进行时,发生选择性环化,该溶剂主要通过 6-内位环化产生 2-苯基萘-1-醇产物,而没有消除或通过关闭 5-外位环化形成环戊[ a ]萘酚。挖掘环化模式。将酸从布朗斯台德酸转换为 Bi(OTf) 3导致反应顺利,以中等至良好的产率提供环戊[ a ]萘酚产物。此外,我们还展示了利用2-苯基萘-1-醇制备萘醌,萘醌是生物活性和天然产物化合物的重要核心结构。
Direct Arylation Reactions Catalyzed by Pd(OH)<sub>2</sub>/C: Evidence for a Soluble Palladium Catalyst
作者:Mathieu Parisien、Damien Valette、Keith Fagnou
DOI:10.1021/jo051039v
日期:2005.9.1
Palladium hydroxide on carbon (Pearlman's catalyst) effectively catalyzes direct arylation reactions of aryl iodides and bromides, providing excellent arylation-to-hydrodehalogenation ratios (> 30:1) with broad scope for both intra- and intermolecular arylation processes. Studies aimed at determining the nature of the active catalyst indicate that an active homogeneous palladium species is produced under the reaction conditions.
Conformational Studies by Dynamic NMR. 89.<sup>1</sup> Stereomutation and Cryogenic Enantioseparation of Conformational Antipodes of Hindered Aryl Oximes
Aryl benzyl oximes having the configuration Z give rise to stereolabile atropisomers when a halogen atom is present in the ortho position of the aryl moiety, as a consequence of the restricted aryl-CN bondrotation. By means of dynamic (1)H NMR spectroscopy it has been possible to determine the corresponding rotationbarrier, hence the lifetime of the atropisomers that, in the case of the iodine derivative