Mechanistic Investigations of Deaminative Benzylic Arylation on Various Diazenes

Details

Supervisors

Elias, Benjamin ; Troian-Gautier, Ludovic

Faculty

Faculté des sciences

Degree label

Master [120] en sciences chimiques, à finalité approfondie

Abstract

Photocatalysis is a distinct category of chemical reactions. It makes use of the energy provided by light to propel processes that would be challenging, if not impossible, to perform in the dark. New synthetic strategies are primordial for total synthesis and the development of new drugs, amongst others. Expanding the scope of achievable transformations highly depends on the understanding of the implied mechanism. In this work, we have focused on a deaminative benzylic arylation reaction reported in 2023 by the Michaudel group. This reaction proceeded via an iridium/nickel cross-coupling allowing the formation of C(sp2)-C(sp3) bonds from C-N bonds. Herein, we provide a mechanistic investigation of the key parameters which control that reaction. This includes the synthesis of four azo compounds as well as the characterisation of the photophysical and electrochemical properties of four iridium complexes. Stern-Volmer experiments were performed to quantify the interactions between the complexes and the diazenes. Nanosecond transient absorption spectroscopy results emphasise that, depending on the design of the iridium photosensitiser, either an electron or an energy transfer can take place between the substrate and the photocatalyst.