Phosphorus ligands with the 1,8-dimethylnaphthalene scaffold

Abstract

In this TFG, the study of the synthesis of different unreported phosphorus ligands based on the 1,8-dimethylnapthalene core has been carried out focusing on synthetic efficiency. The first part focuses on the synthesis of 1,8-dimethylnaphthalene (5) from naphthalic anhydride (1) involving a variety of synthetic methods and experiments that resulted into an efficient synthesis of 5. This compound has been characterized to ensure its purity to be used for the preparation of a P-phenylphosphorinane (8).Taking advantage of the precursors prepared for the synthesis of 5, two unreported ligands have also been synthesized, which can open the door to other interesting ligands for homogeneous catalysis: a bisphosphinite ligand (6) and an eight-membered cyclic phosphonite ligand (7). Both ligands have been characterized, including the selenide of 7, which allowed the evaluation of its donor properties. In addition, preliminary complexation studies of 7 with palladium(II) and ruthenium(II) precursors have been performed.Finally, the challenging synthesis of a novel 6-membered ring phosphorus heterocycle from precursor 5, the P-phenylphosphorinane 8, has also been performed by cyclisation of dilithiated 5 with dichlorophenylphosphine. Numerous difficulties, modifications, drawbacks and uncertainties had to be faced but it seems that the desired compound has been finally obtained and will be purified in future studies.