Novel carbohydrate olefin hybrid ligands in rhodium catalyzed reactions: Challenging substrates in 1,4-additions

在第一个资助期，以手性碳水化合物为基础，合成了一系列新的具有烯烃和亚磷酸酯结构的手性杂二酸酯配体。这些配体是可及性较好的假对映异构体杂化配体，成功地应用于不对称催化的1，4-加成反应中。在这里，我们计划用核磁共振波谱详细地研究具有挑战性的亲核试剂如杂芳基硼酸盐的不对称催化1，4-加成反应，以确定和解决出现的问题。此外，在反应中将使用有问题的亲电体，例如具有外环受体取代基的环烯类化合物，例如环烯-1-碳腈。在此基础上，将实现各种药物的合成，如(-)-帕罗西宁。此外，在C2取代的环戊烯上的不对称催化1，4-加成反应也将被用来合成类固醇激素马精氨酸。1，3-二恶英-4-酮上的1，4-加成是未知的，将作为3-羟基羰基化合物的一种新途径而被仔细研究。最后，将进行两个项目路线相结合的定向实验。

In the first funding period a number of new chiral heterobidendate ligands with an alkene and a phosphite moiety were prepared based on carbohydrates from the chiral pool. These ligands are well accessible, pseudo-enatiomeric hybrid ligands, which were successfully employed in asymmetric rhodium-catalyzed 1,4-additions. Here we plan to investigate in detail asymmetric catalytic 1,4-additions with challenging nucleophiles such as heteroarylboronates by NMR spectroscopy in order to identify and solve occurring problems. Further, problematic electrophiles such as cycloalkenes with an exocyclic acceptor substituent, e. g. cycloalkene-1-carbonitriles, will be employed in the reaction. On this basis the synthesis of various medicinal drugs, e. g. (-)-paroxenine, will be achieved. In addition, the so far unprecedented asymmetric catalytic 1,4-addition at C2-substituted cyclopentenes will be investigated for synthesizing the steroid hormone equilenine. 1,4-Additions at 1,3-dioxin-4-one are unknown and will be scrutinized as a new access to 3-hydroxycarbonyl compounds. Finally orienting experiments with a combination of the two project lines will be undertaken.