Cycloadducts from highly functionalized nitrones and oximes as ligands in the enantioselective addition of diethylzinc to benzaldehyde
作者:Subramanian Baskaran、Hans Günter Aurich、Frank Biesemeier、Klaus Harms
DOI:10.1039/a806744i
日期:——
Highly diastereoselective intramolecular cycloaddition of nitrones 5–7 and 16, as well as oximes 11–13 that are easily accessible from diethyl (R,R)-tartrate, affords bicyclic compounds 8–10 and 17. The tetracyclic compound 14 is formed as the main product by an intramolecular domino reaction of dioxime 11. Some of the bicyclic compounds and the tetracyclic compound 14 are tested as chiral ligands in the enantioselective addition of diethylzinc to benzaldehyde. An ee of 93% was achieved in the presence of the best ligand.
硝基 5-7 和 16 以及易于从(R,R)-酒石酸二乙酯中获得的肟 11-13 发生高非对映选择性分子内环加成反应,生成双环化合物 8-10 和 17。四环化合物 14 是二恶肟 11 分子内多米诺反应的主要产物。在二乙基锌与苯甲醛的对映体选择性加成反应中,部分双环化合物和四环化合物 14 作为手性配体进行了测试。在最佳配体存在的情况下,ee 达到 93%。