Taylor Jordan W, Harman W Hill
Department of Chemistry, University of California, Riverside, CA 92521, USA.
Chem Commun (Camb). 2020 Apr 25;56(32):4480-4483. doi: 10.1039/d0cc01142h. Epub 2020 Mar 23.
The boron-centered reactivity of the diboraanthracene-auride complex [Au(BP)][K(18-c-6)]; (BP, 9,10-bis(2-(diisopropylphosphino)-phenyl)-9,10-dihydroboranthrene) with a series of organic carbonyls is reported. The reaction of [Au(BP)] with formaldehyde or paraformaldehyde results in a head-to-tail dimerization of two formaldehyde units across the boron centers. In contrast, the reaction of [(BP)Au] with two equivalents of benzaldehyde yields the pinacol coupling product via C-C bond formation. Careful stoichiometric addition of one equivalent of benzaldehyde to [Au(BP)] enabled the isolation of an adduct corresponding to the formal [4+2] cycloaddition of the C[double bond, length as m-dash]O bond of benzaldehyde across the boron centers. This adduct reacts with a second equivalent of benzaldehyde to produce the pinacol coupling product. Finally, the reaction of [Au(BP)] with acetone results in a formal reductive deoxygenation with discrete hydroxo and 2-propenyl units bound to the boron centers. This reaction is proposed to proceed via an analogous [4+2] cycloadduct, highlighting the unique small molecule activation chemistry available to this platform.
报道了二硼蒽-金化物配合物[Au(BP)][K(18-c-6)]（BP为9,10-双(2-(二异丙基膦基)-苯基)-9,10-二氢硼蒽）与一系列有机羰基化合物以硼为中心的反应活性。[Au(BP)]与甲醛或多聚甲醛反应导致两个甲醛单元在硼中心处发生头对尾二聚化。相比之下，[(BP)Au]与两当量苯甲醛反应通过碳-碳键形成生成频哪醇偶联产物。将一当量苯甲醛小心地按化学计量加入[Au(BP)]中，能够分离出一种加合物，该加合物对应于苯甲醛的碳-氧双键在硼中心处的形式上的[4+2]环加成。该加合物与第二当量苯甲醛反应生成频哪醇偶联产物。最后，[Au(BP)]与丙酮反应导致形式上的还原脱氧反应，硼中心处结合有离散的羟基和2-丙烯基单元。该反应被认为是通过类似的[4+2]环加合物进行 的，突出了该平台可用的独特小分子活化化学。
