Novel catalytic transformations mediated by dual photoredox and earth abundant transition metals

The main purpose of my doctoral studies was the development of new organic methodologies combining photoredox-and metal catalysis, termed metallaphotoredox catalysis. In this dissertation thesis four novel protocols are reported. Each of them introduces innovative and unprecedented aspects in the metallaphotoredox field. In particular, 1) A dual photoredox-and cobalt-catalyzed protocol for the allylation of carbonyl groups is reported. The innovative aspect is the introduction of a novel TADF (Thermally Activated Delayed Fluorescence)-emitter photocatalyst derived from the degradation of the commercially available 3DPAFIPN, which can sustain the dual catalytic protocol, where the latter and other common TADF-emitters failed. Then, 2) A dual photoredox-and vanadium-catalyzed protocol for the diastereoselective pinacol coupling of aromatic aldehydes is described. The use of vanadium under photoredox conditions for the functionalization of small molecules is an underexplored field, since only few papers are reported in the literature. The key aspects of this work are the high reactivity and the high functional group tolerance of the vanadium complex used. Then, 3) A dual photoredox-and nickel-catalyzed protocol for the diastereoselective allylation of carbonyl groups using Morita-Baylis-Hillman acetates (MBH acetates) is described. The key aspect of this work is the use of MBH acetates as unprecedented pronucleophiles. The protocol was found to be highly regio- and diastereoselective, and tolerant to different functional groups. The products are useful intermediates for the synthesis of bioactive molecules, and few synthetic manipulations of the standard allylated product are reported. Finally, 4) A dual photoredox-and titanium-catalyzed protocol for the allylation of carbonyl groups using 4-bromo crotonates is reported. The key aspect of this work is the use of 4-bromo crotonates as an unprecedented allyl source under photoredox/vinylogous conditions for the fast, highly regioselective and moderately diastereoselective synthesis of α-vinyl-β-hydroxy esters. The presence of multiple functional groups was exploited with some post-functionalization.