Toward novel REActivity in Carbene Transfer reactions provided by PHTHALocyanine catalysts – REACTPHTHAL

CCarbene transfer to X-H bonds (X=N, C, S, Si) has emerged as a powerful strategy for construction of elaborated molecules. These versatile and atom-economic reactions are efficiently catalyzed by porphyrin complexes and engineered hemoproteins and involve carbenoid metal species. In contrast, cheap and industrially available phthalocyanines (MPc) are almost not studied in these reactions. Although MPc have been often considered as porphyrin analogues, their catalytic properties do differ from those of porphyrins. Increasing number of studies shows that MPc are superior to porphyrins in many reactions and often show particular reactivity. Our recent research confirmed singular properties of MPc in carbene transfer reactions. In particular, MPc show unprecedented reactivity in challenging N-H carbene insertion providing unsymmetrical tertiary amines and diamines as well as diaminoacid derivatives from readily available amines in one step with high yields and high turnover numbers. Importantly, these novel compounds cannot be obtained using porphyrin, enzyme or other metal catalysts. In this project we will explore these novel reactions in details. First, the scope will be extended to aliphatic, substituted aromatic, polyfunctionalized amines and aminoacids. Then, the variety of diazo compounds (11 carbene precursors) will be evaluated aiming on the preparation of diamine derivatives bearing different structural motifs. Taking advantage of our recent preparation of the first chiral picket-fence metal phthalocyanine with menthoxy groups creating chiral surrounding of the metal sites, the enantioselective reaction will be explored. The search for the novel reactivity will be performed in the S-H carbene insertion because of the mechanistic similarity of N-H and S-H insertion reactions. In the study of Si-H and C-H insertion reactions, an emphasis will be placed on the development of accessible earth-abundant catalysts showing high efficiency as an alternative to current methods based on noble metal complexes showing low-to-moderate turnover numbers. In all X-H insertion reactions, we will search for the novel synthetic pathways to elaborated structures. Thus, the compounds containing benzylic C-H bonds, allylic and those close to heteroatoms including heterocyclic fragments will be evaluated. We will also explore the formation of unsymmetrical silane derivatives with four different substituents starting from available R1R2SiH2 compounds using our novel approach involving successively two different carbene precursors. We have recently validated this approach to access to unsymmetric tertiary amines.
Along with development of the novel synthetic approach in carbene transfer chemistry, it is of utmost importance to determine the reason of the unusual reactivity which will help to obtain more performant catalysts. The catalytic properties should be sensitive to the distribution of electronic and spin density, hence to the ligand nature. To get insight into structural and electronic properties governing the catalytic activity, we will study MPc and active metal carbene species which can adopt different electronic states by advanced spectroscopic methods (EXAFS, XANES). Thus, the project goal is to develop previously over-looked mono- and binuclear phthalocyanines for rapidly expanding area of carbene transfer reactions and to explore the novel reactivity that might provide elaborated organic compounds with interesting biological and pharmacological properties.