Design, synthesis and applications of phosphines and amines embedded triptycenes : exploring new reactivities in main-group and organometallic chemistry

This Ph.D. work was focusing on the development of sterically hindered Lewis bases, in particular triaryl phosphines and amines, which then were employed for the rational design of frustrated Lewis pair catalysts. In this context, we prepared new types of FLPs by combining strong boron Lewis acids with the group XV (N, P) derived 9-hetero-triptycene. Initially, several novel synthetic approaches enabling the access to the 9-azatriptycene framework were attempted. We then turned our attention to the preparation of sterically hindered 9-phosphatriptycene scaffold. Two methodologies were developed allowing to reach unprecedented ortho-substituted unsymmetrical 9-phosphatriptycene derivatives which include the first example of P-chirogenic 9-phosphatriptycene ever reported. By means of computational and experimental methods, the unique electronic and steric properties, and Brønsted and Lewis basicities of 9-phosphatriptycenes were quantified. The coordination of 9-phosphatriptycenes with transition metal [Rh(III) and Au(I)] was finally investigated and the resulting complexes were studied and characterized by IR, NMR, and X-ray diffraction crystallography. Lastly, the association of phosphatriptycenes with tris(pentafluorophenyl)borane was experimentally tested and applied as FLP catalyst, enabling the transition-metal-free hydrogenation reaction of unactivated alkenes under mild reaction condition.(SC - Sciences) -- UCL, 202