Development of Transition Metal Catalysts with Optical Active [2.2] Paracyclophanebisphosphine Ligands

我们合成[2.2]对环芳双膦配体的最初计划是二聚桥接双（对亚二甲苯基）中间体以选择性地实现所需的伪邻位双取代。虽然通过新开发的路线顺利制备了反应中间体的前体，但分子内的二聚化失败，可能是由于难以产生双当我们检查以假邻位方式选择性引入两个溴原子的反应条件时，美国的Merck研究小组报道了涉及[2.2]对环凡双膦-钌和钯络合物的合成和催化活性的完全相同的项目。然而，其合成路线的瓶颈是从溴化产物的复杂混合物中分离假邻位二溴化物的繁琐过程。在我们的初步研究中，从理论和实验两方面得出了溴蒸气与粉末状[2.2]对环芳之间的气-固反应是假邻位选择性的结论。作为相关的C2手性环蕃配体，我们成功地合成和拆分了由环状Tr_格尔碱衍生的双齿氮配体。

Our initial plan to synthesize the [2.2]paracyclophanebisphosphine ligand was to dimerize a bridged bis(p-xylylene) intermediate to realize the desired pseudo-ortho disubstitution selectively. Although the precursor of the reaction intermediate was prepared smoothly via a newly developed route, the intramolecular version of the dimerization failed, possibly due to difficulty of generating the bis(p-xylylene) intermediate.While we were examining the reaction conditions for selective introductionm of two bromine atoms in a pseudo-ortho fashon, exactly the same project dealing with the synthesis and catalytic activity of [2.2]paracyclophanebisphosphine- ruthenium and palladium complexes was reported by a Merck research group in U.S.A.However, the bottleneck of their synthetic route was the tedius separation of the pseudo-ortho dibromide from a complex mixture of bromination products. In our preliminary studies, both theoretically and expermentally, we arrived at the conclusion that gas-solid reaction between bromine vapor and powdered [2.2]paracyclophane would be pseudo-ortho selective. Improvement of the rection conditions is now underway.As the related C2 chiral cyclophane ligands, we succeeded in the synthesis and resolution of bidentate nitrogen ligands derived from cyclic Tr_ger bases.