Optical resolution of racemic stilbenediamine using N*-chiral ortho-palladated matrix

Article abstract of DOI:10.1007/BF02494426

Optical resolution of racemic stilbenediamine (Stien) was performed by recrystallization of its diastereomeric adducts with ortho-palladated (S)-N-isopropyl-α-methylbenzylamine. The less soluble (S_CR_N,SS) diasteteomer was studied by X-ray diffraction analysis. It was established that the crystal of this diastereomer consists of dimers formed via association of two molecules of the mononuclear cationic complex with an additional molecule of free diamine of the same absolute configuration. The association occurs through a system of hydrogen bonds and weak agostic interactions. Based on the X-ray diffraction data, the procedure was improved for the resolution of stilbenediamine due to the more profitable use of the ortho-palladated reagent. The Stien/Pd ratio in the diastereomer isolated was increased up to 3 : 2. The conformational features of the complex are discussed on the basis of ¹H NMR spectroscopy data.