Synthesis and applications of chiral catalysts based on heterocyclic units

The present PhD Thesis was mainly focused on the synthesis and the applications of chiral catalysts based on heterocyclic units.
As an appendix of the manuscript, the work concerning my abroad period spent at the University of Glasgow is reported, whose research topic was the synthesis of benzoxazoles through a one-pot two-step procedure involving the use of first iron(III) and copper(I) catalysis for the second step. The fields of catalysis investigated are the Lewis Base, the Brønsted acid catalysis and finally the catalysis promoted by phosphoramidites. As a contribution for the stereoselective Lewis Base catalysis, the synthesis and the resolution of TetraPh-Tol-BITIOPO (Chapter 1, 37) was carried out, whose application can be considered a further investigation of the huge potentialities of the 3,3’-bithiophenic enantiopure TetraMe-BITIOPO in Lewis-base catalysed Lewis-acid mediated reactions. For what concern Brønsted acid catalysis, a new chiral phosphoric acid based on a decahydroquinoxalinic scaffold bearing in the position 2 and 3 two thienylic units (Chapter 2, 19) was synthesized and tested in two preliminary stereoselective organocatalytic transformations. Based on the same decahydroquinoxalinic backbone, we decided to design a new heterocyclic- based diphosphinoxide (Chapter 2, 42). In Chapter 3, a new heterocyclic phosphoramidite based on a 3,3’-bithiophenic scaffold (L6) was synthesized and employed in combination with a copper salt in some catalytic stereoselective 1,4- additions of diethyl zinc to enones and trisubstituted nitroalkenes.