Reseach on Preparation and Properties of the dpcb Ligand and Their Metal Complexes Containing Various Functional Groups

带有极其庞大的2，4，6-三叔丁基苯基（缩写为Mes^* 基团）的空间保护的3，4-二膦杂环丁烯（下文缩写为DPCB）是独特的感兴趣的双齿配体，因为它们含有磷-碳π-键的相对刚性的骨架。我们制备了各种DPCB的过渡金属配合物，并将其中一些用作均相催化剂。我们最近合成了1，2-二（2-噻吩基）-3，4-二膦杂环丁烯（DPCB-T）和1，2-二（3-噻吩基）-同系物（DPCB-T ′），以及一些含有DPCB-T重复单元的聚合物。DPCB-T和DPCB-T都是用于构建更精细的DPCB衍生物的有前景的构建块，因为官能团（在硫原子的位置a处）的引入预期在温和条件下容易地进行。事实上，各种DPCB-T衍生物是通过与丁基锂化，然后与亲电试剂反应来制备的。此外，Mon 关于我们 通过DPCB-T与丁基锂和碘乙腈的连续反应，得到了o-和二碘-DPCB-T衍生物。然后进行碘代-DPCB-T衍生物的进一步转化：引入各种炔基，如三甲基甲硅烷基乙炔基、吡啶基乙炔基或甘菊环基乙炔基，得到新的DPCB配体。还合成了一些1，2-位带有噻吩基或奥基的新型3，4-二膦杂环丁烯。此外，如下开发了新型间隔物。在我们继续研究开发上述新型有机磷配体的过程中，我们对含有2，3-噻吩基间隔基的配体系统产生了兴趣。2，3-亚噻吩基间隔基具有优点：容易将取代基或官能团引入噻吩环的5-位。这一优势将有助于例如对复杂配体的研究。然后，我们研究了1，4-双（2-乙炔基-3-噻吩基）苯的制备及其在吡啶配体中的应用，其中双（乙炔基噻吩基）苯部分作为间隔基引入。少

Sterically protected 3,4-diphosphinidenecyclobutenes (hereafter abbreviated to DPCB), bearing an extremely bulky 2,4,6-tri-t-butylphenyl group (abbreviated to the Mes^* group), are unique bidentate ligands of interest, because of their relatively rigid framework containing the phosphorus-carbon π-bond. We have prepared various transition metal complexes of DPCB and some of them were used as homogeneous catalysts. We recently prepared 1,2-di(2-thienyl)-3,4-diphosphinidenecyclobutene (DPCB-T) and 1,2-di(3-thienyI)- congener (DPCB-T'), as well as some polymers bearing repeating unit containing the DPCB-T moiety. Both DPCB-T and DPCB-T are promising building blocks for construction of more elaborate DPCB derivatives, because introduction of functional group (at the position a to the sulfur atom) is expected to be easily performed under mild conditions. In fact, various DPCB-T derivatives were prepared by lithiation with butyllithium followed by reaction with electrophiles. Furthermore, mon … More o-and diiodo-DPCB-T derivatives were obtained by successive reactions of DPCB-T with butyllithium and iodoacetonitrile. Further conversions of the iodo-DPCB-T derivatives were then carried out : Various alkynyl groups, such as trimethylsilylethynyl, pyridylethynyl, or azulenylethynyl, were introduced to give new DPCB ligands. Some novel 3,4-diphosphinidenecyclobutenes, bearing thienyl or azulenyl group at the 1,2-positions, were also prepared. In addition, novel spacer was developed as follows. In the course of our continuing researches on developing novel organophosphorus ligands as mentioned above, we interested in the ligand system containing the 2,3-thienylene spacer. The 2,3-thienylene spacer has an advantage : introduction of substituents or functional groups into the 5-position of the thiophene ring is easy. This advantage will help, for example, researches on sophisticated ligands. We then investigated preparations of 1,4-bis(2-ethynyl-3-thienyl)benzene and its application to pyridine ligands, in which the bis(ethynylthienyl)benezene moiety is incorporated as a spacer. Less