Regioselectivity of Birch Reductive Alkylation of Biaryls
作者:Raphaël Lebeuf、Frédéric Robert、Yannick Landais
DOI:10.1021/ol051377i
日期:2005.10.1
regioselectivity of the Birchreductive alkylation of polysubstituted biaryls has been investigated. Results indicate that regioselectivity is affected by the electronic nature of substituents on both aromatic rings. The electron-rich 3,5-dimethoxyphenyl moiety is selectively reduced and then alkylated, while phenols and aniline are not dearomatized under these conditions. Biaryls possessing a phenol moiety are
A new cascade radical reaction for the synthesis of biaryls and triaryls from benzyl iodoaryl ethers
作者:David C Harrowven、Michael I.T Nunn、Nicola A Newman、David R Fenwick
DOI:10.1016/s0040-4039(00)02111-0
日期:2001.1
The paper describes a new method of synthesizing biaryls and triaryls through an intramolecular ipso-substitution reaction initiated by the addition of an aryl radical to a benzyl ether. A tandem variant of the reaction has also been demonstrated. A short synthesis of isoaucuparin 27, a natural product found in the sapwood tissue of Sorbus aucuparia, is also described.
2-Arylphenols were conveniently synthesized from aryl iodides and 6-diazo-2-cyclohexenones, In moderate to excellent yields, via tandem Pd-catalyzed cross-coupling/aromatization. The preliminary results for the corresponding enantioselective version showed that the coupling products could be generated In up to 72% ee.
Solution and Solid-State Studies on the Halide Binding Affinity of Perfluorophenyl-Armed Uranyl-Salophen Receptors Enhanced by Anion-π Interactions
enhancement of the binding between halide anions and a Lewis acidic uranyl–salophen receptor has been achieved by the introduction of pendant electron‐deficient arene units into the receptor skeleton. The association and the occurrence of the elusive anion–π interaction with halide anions (as tetrabutylammonium salts) have been demonstrated in solution and in the solidstate, providing unambiguous evidence
5-dimethoxyphenyl moiety and a phenol ring may, however, be reduced and alkylated provided the acidic phenolic proton is removed prior to the treatment with Li in NH3. Similarly, biaryls possessing a o-sulfonamide group are reduced regioselectively and alkylated with α-chloroacetonitrile or N-tosylaziridine to provide the corresponding dienes in reasonable to good yields. A survey of the alkylating agents was also
通过改变芳环上取代基的性质,进行了联芳基的桦树还原性烷基化。我们的研究集中在富含电子的取代基(例如OMe,OH和NR 2基团)上,因为它们存在于目标生物碱的骨架上。区域选择性受两个环上这些取代基的电子性质的强烈影响。3,5-二甲氧基苯基部分被选择性还原然后烷基化,而苯酚和苯胺在这些条件下不发生反应。但是,只要在用Li在NH 3中处理之前除去酸性酚质子,就可以还原同时具有3,5-二甲氧基苯基部分和酚环的联芳基并烷基化。类似地,联芳基化合物具有一个Ô-磺酰胺基区域选择性地还原,并用α-氯乙腈或N-甲苯磺酰基氮丙啶烷基化,以合理至良好的产率提供相应的二烯。还对烷基化剂进行了调查,结果表明可以在苄基位置引入各种官能团,包括酯,伯和叔酰胺,腈,环氧化物和乙缩醛,以及未官能化的空间位阻t- Bu基和环丙基取代基。引入后者的表示两个A S Ñ 2和SET机构可以在所述烷基化步骤进行。