Chiral 8-Amino-5,6,7,8-tetrahydroquinoline Derivatives in Metal Catalysts for the Asymmetric Transfer Hydrogenation of 1-Aryl Substituted-3,4-dihydroisoquinolines as Alkaloids Precursors

Abstract

Chiral diamines based on an 8-amino-5,6,7,8-tetrahydroquinoline backbone, known as CAMPY (L1), or the 2-methyl substituted analogue Me-CAMPY (L2) were employed as novel ligands in Cp* metal complexes for the ATH of a series of substituted dihydroisoquinolines (DHIQs), known for being key intermediates in the synthesis of biologically active alkaloids. Different metal-based complexes were evaluated in this kind of reaction, rhodium catalysts, C3 and C4, proving most effective both in terms of reactivity and enantioselectivity. Although modest enantiomeric excess values were obtained (up to 69% ee in the case of substrate I), a satisfactory quantitative conversion was successfully fulfilled even in the case of the most demanding hindered substrates when La(OTf)3 was used as beneficial additive, opening up the possibility for a rational design of novel chiral catalysts alternatives to the Noyori-Ikariya (arene)Ru(II)/TsDPEN catalyst.

Cytotoxic Pt(ii) complexes containing alizarin: a selective carrier for DNA metalation

“…From a structural point of view, computations evidenced that all the complexes are characterized by a square planar structure in which the O^O and the N^N ligands, when fully aromatic, are coplanar to each other. While a distortion from the planarity on the N^N ligand can be observed, as expected, when one or both nitrogen atoms coordinated to the platinum center are sp 3 . The nature of the N^N ligands has only a marginal influence on the Pt-N and Pt-O bond lengths, as previously reported for some aquo complexes with similar nitrogen ligands.…”

“…One of the greatest successes of medicinal inorganic chemistry is the discovery of Pt(II) anticancer agents, medically used for over 30 years in the treatment of various tumours. [1][2][3][4] Three anticancer Pt(II)-based drugs (cisplatin, carboplatin and oxaliplatin) are in clinical use worldwide, while an additional four are exclusively approved in selected countries (nedaplatin and miriplatin in Japan, lobaplatin in China and heptaplatin in South Korea) (Fig. 1).…”