A fast and operationally simple method for the aerobic homocoupling of arylboronic acids is described. The process is catalyzed by Pd(II) complexes supported on the metal‐organic framework MIL‐88B‐NH2(Cr). The benefits of this approach include the use of a benign oxidant/solvent mixture at room temperature with catalytic amounts of base, easy recovery of the catalyst, and easy isolation of the products
o-methoxybenzaldehydes tend to associate in a centrosymmetric fashion, akin to the carboxylicacids, to give rise to a dimer motif II, which derives stabilization from four C–H⋯O hydrogenbonds in addition to a dipole–dipole interaction. That the synthon II is credible to be structure determining is revealed from the crystalstructures of aldehydes 1–4 that are devoid of any other competing weak interactions
摘要 我们通过对一组醛的合理设计、合成和 X 射线结构分析表明,邻甲氧基苯甲醛倾向于以中心对称方式缔合,类似于羧酸,产生二聚体基序 II,其衍生除了偶极 - 偶极相互作用之外,还可以通过四个 C-H⋯O 氢键稳定。从没有任何其他竞争性弱相互作用的醛 1-4 的晶体结构中可以看出合成子 II 是可信的结构决定因素。发现醛 1-4 自组装成一维分子带和楼梯。我们已经表明,醛 5 中的空间因子和 6 中诸如 Br 等官能团的存在扰乱了基于合成子 II 的预期晶体堆积。
A New Protocol for the One-Pot Synthesis of Symmetrical Biaryls
作者:Carl F. Nising、Ulrike K. Schmid、Martin Nieger、Stefan Bräse
DOI:10.1021/jo0490393
日期:2004.10.1
Biaryls play an important role in modern organic chemistry. Although a large number of protocols, for the synthesis of symmetrical and unsymmetrical biaryls already exist, most of them are not generally applicable. In our studies toward the total synthesis of the secalonic acids, we were interested in bis(pinacolato)diboron as a reagent for transforming haloarenes into arylboronic esters. By optimizing the reaction conditions, we were able to obtain biaryls containing various functional groups in good to excellent yields.
Homodinuclear Ruthenium Catalysts for Dimer Ring-Closing Metathesis
作者:Eyal Tzur、Amos Ben-Asuly、Charles E. Diesendruck、Israel Goldberg、N. Gabriel Lemcoff