News about the diagonal relationship between phosphorus and carbon: development of 5-phosphasemibullvalene derivatives and their application as P(III)-Ligands in homogeneous catalysis

我们在2016年首次描述的1-磷酸二烯二π-甲烷重排到5-磷酸半烯衍生物，代表了元素周期表中磷和碳元素之间一种新的有趣的对角线关系。它提供了一种简单和选择性的获得手性，立体要求，刚性和构型稳定的有机磷（III）化合物的途径。第一期资助期（2017-2020年）对5-磷酸半球戊烯衍生物的光诱导生成进行了系统的基础研究。在此过程中，我们不仅能够获得关于这些磷化合物的合成、配位化学和对映体分离的重要结果，而且还可以获得关于它们的立体电子性质以及它们作为配体在Au(I)催化的环化反应和rh催化的端烃和内烃的氢甲酰化反应中的应用的重要信息。此外，通过DFT计算还获得了配合物结合的1-磷酸二烯二π-甲烷重排机理的重要信息。部分研究结果已经发表在四份同行评议的期刊上，或在一系列讲座中发表。至少还有两份出版物正在编写中。此外，在金属配位球中，1-磷酸二烯二π-甲烷重排为5-磷酸半烯衍生物被认为是一个“亮点”。并就此课题撰写了论文。第二个资助期的重点是i)双齿/螯合5-磷酸半球戊烯的开发；配位化合物中的二π-甲烷重排；Iii)获取未知的2-磷酸半戊烯；Iv)机械调查；V)在前手性烯烃的对映选择性氢甲酰化反应中建立（对映纯的）5-磷酸半戊烯。重点是对映选择性铑催化的内部和反应性较低的烷基烯烃与相应的手性（内部）醛的氢甲酰化。对于这种极具挑战性的反应，迄今为止文献中已知的选择性分子催化剂体系非常少。

The di-π-methane rearrangement of 1-phosphabarrelenes to 5-phosphasemibullvalene derivatives, which we first described by us in 2016, represents a new and interesting diagonal relationship between the elements phosphorus and carbon in the periodic table of the elements. It provides an easy and selective access to chiral, sterically demanding, rigid and configurationally stable organophosphorus(III) compounds. In the first funding period (2017-2020), the photoinduced formation of 5-phosphasemibullvalene derivatives was investigated fundamentally and systematically. In doing so, we were not only able to obtain important results regarding the synthesis, coordination chemistry and separation of enantiomers of these phosphorus compounds, but also important information about their stereoelectronic properties as well as their use as ligands in Au(I)-catalysed cyclization reactions and in the Rh-catalyzed hydroformylation of terminal and internal alkenes could be gained. Furthermore, valuable information on the mechanism of di-π-methane rearrangement of complex-bound 1-phosphabarrelenes was obtained by means of DFT calculations. Parts of the results have already been published in four peer-reviewed journals or presented in a series of lectures. At least two further publications are in preparation. Also, the di-π-methane rearrangement of 1-phosphabarrelenes to 5-phosphasemibullvalene derivatives in the coordination sphere of metals was acknowledged as a "highlight". Furthermore, a dissertation was written on this project. The focus of the second funding period is in particular i) the development of bidentate/chelating 5-phosphasemibullvalene; ii) di-π-methane rearrangement in coordination compounds; iii) access to still unknown 2-phosphasemibullvalenes; iv) mechanistic investigations; v) the establishment of (enantionmerically pure) 5-phosphasemibullvalenes in the enantioselective hydroformylation of prochiral alkenes. The focus is on the enantioselective Rh-catalyzed hydroformylation of internal and less reactive alkyl-alkenes to the corresponding chiral (internal) aldehydes. For this extremely challenging reaction, there are so far only very few selective molecular catalyst systems known in the literature.