Development of novel molecular catalysts having tetraphenylphenyl unit

我们阐明了具有刚性和空间分布结构的四苯基配体的功能。合成了含四苯基的氧、氮、磷配体，并考察了它们在几种金属催化下的催化反应。我们的目标是找到新的反应，高催化活性，高选择性相比，传统的催化剂。事实上，在过去的一年里，我们已经探索了由四苯基苯基产生的大的不对称环境对立体选择性的增强作用。四苯基苯基基团的尺寸约为1.3纳米。这比通常的均相金属络合物催化剂中使用的配体相对更大，然而，比超分子催化剂如树枝状聚合物更小。超分子催化剂的一个优点是合成的可及性。实际上，我们已经研究了2，2 '-二羟基-1，1'-联芳基乙烯基醚的不对称醇解反应，发现 关于我们 含四苯基苯基的二胺配体表现出更高的性能：立体选择性提高1.3倍，催化活性提高2.0倍。该反应是非常有用的，因为不对称合成2，2 '-二羟基-1，1'-联萘酚相对容易，但2，2 '-二羟基-1，1'-联苯酚不那么容易。其原因主要是由于反应过程中产生的自由基的稳定性。因此，2-萘酚的氧化偶联是容易的，而苯酚是困难的。我们将研究扩展到具有磷酰基和磺酰基的2，2 '-二羟基-1.1'-联芳化合物的不对称合成，并成功地高选择性地对这些化合物进行了动力学拆分。此外，对磷原子上具有不对称中心的化合物进行了动力学拆分研究，发现该类化合物的动力学拆分选择性高达39。由于这些化合物的不对称合成是极其困难的，我们的反应的价值应该是非常高的。少

We have elucidated that the function of ligands bearing tetraphenylphenyl group, which have rigid and spatially spread structure. The oxygen-, nitrogen-, and phosphorous-ligands having tetraphenylphenyl group were synthesized and were examined catalytic reactions using several kinds of metals. We aimed to find new reactions, high catalytic activity, and high selectivity compared to conventional catalysts. Indeed, in the last year we have explored the enhancement effect of stereoselectivity by the large asymmetric environment produced by tetraphenylphenyl group. The size of the tetraphenylphenyl group is approximately 1.3 nano meters. This is relatively larger than the ligands, which is used in usual homogeneous metal complex catalysts, however, smaller than supermolecular catalysts such as dendrimers. An advantage over the supermolecular catalysts is synthetic accessibility. In reality, we have examined asymmetric alcoholysis of vinyl ethers of 2,2'-dihydroxy-1.1'-biaryls and found tha … More t the diamine ligands bearing tetraphenylphenyl group exhibited higher performance : 1.3 times higher stereoselectivity and 2.0 times higher catalytic activity. This reaction is very useful because asymmetric synthesis of 2,2'-dihydroxy-1.1'-binaphtols is relatively easy but 2,2'-dihydroxy-1.1'-binphenols are not so easy. The reason is mainly due to the stability of radicals generating during the reaction. Therefore oxidative coupling of 2-naphtol is easy but phenol is difficult. We extended the research to the asymmetric synthesis of 2,2'-dihydroxy-1.1'-biaryls having phosphoryl and sulfonyl groups and succeeded kinetic resolution of these compounds in high selectivity. In addition, the compounds which have asymmetric center at phosphorous atom were examined to the reaction and found that kinetic resolution of these class of compounds can be carried out with high selectivities up to 39. Since asymmetric synthesis of these compounds are extremely difficult, the value of our reactions should be very high. Less