Photoredox radical conjugate addition of dithiane-2-carboxylate promoted by an iridium(iii) phenyl-tetrazole complex: a formal radical methylation of Michael acceptors

Abstract

An iridium(iii) phenyl-tetrazole complex is a versatile catalyst for a new photocatalytic Michael reaction.

Phosphorescent bio-based resin for digital light processing (DLP) 3D-printing

“…It should be mentioned that cyclometalated Ir(III) complexes have been previously employed to generate reactive radical species upon light irradiation. [61][62][63] Therefore, we explored the possibility of employing the luminescent additives as photopolymerization initiators, but no hardening of the resin was observed for concentrations up to 0.5 wt% and irradiation times up to 10 s. Emission spectra of 3D printed luminescent dog-bones revealed that the emissive behaviour of the complexes has been maintained after the photopolymerization (Fig. 8a).…”

Advances in the Synthesis of Methylated Products through Indirect Approaches

“…Under photoredox reaction conditions, carboxylic acids have been successfully applied as the alkyl radical equivalent for decarboxylative Michael additions . However, the generation of the methyl radical from acetic acid is still challenging for photocatalytic reactions . In general, the addition of methyl radicals, using an ambitious method based on a Minisci‐type reaction, has still not been well developed in photocatalysis .…”

“…devised 1,3‐dithiane‐2‐carboxylic acid ( 25 ) as the starting material to react with a readily accessible and less costly iridium photocatalyst ( 26 ) to obtain the methyl radical precursor ( 27 ) under photoredox conditions. The radical Michael conjugation leads to the dithiane‐substituted products ( 28 ), which react with Raney‐Ni to give the methylated products ( 30 ) (Scheme ) …”

In My Element: Iridium

“…Its organometallic compounds are typically very stable and can glow intense luminescence all across the Vis region through rational design of the ligand environment . Thanks to its remarkable stability in several oxidation states, it is a key chemical element in industrial catalytic processes, solar‐driven photoelectrochemistry and in the expanding area of photoredox catalysis …”