Seminar by Prof. Claire Empel, RWTH Aachen University, Institute of Organic Chemistry, Germany, on "Leveraging C–H Functionalization Reactions via Excited State Chemistry"

31 Mar 2023
Seminar Room # 350, second floor annex

Speaker: Prof. Claire Empel
RWTH Aachen University, Institute of Organic
Chemistry, Landoltweg 1, 52074 Aachen, Germany.

Title: “Leveraging C–H Functionalization Reactions via
Excited State Chemistry.”

Day and Date: Friday, March 31, 2023

Time: 11.00 am.

Venue: Room no. 350, Chemistry Department
Second floor, Annex

Talk Title : “Leveraging C–H Functionalization Reactions via Excited State Chemistry.”
Abstract
C–H functionalization is considered as one of the key strategies to leverage synthesis to the challenges of the 21st century. It allows for the direct installation of new functional groups onto molecular scaffolds via the manipulation of unreactive C–H bonds without the need of prior functionalization, yet often requiring forcing reaction conditions. Visible light-mediated C–H functionalization reactions open up new possibilities for the selective straightforward functionalization of C–H bonds at ambient conditions.1 For example, visible light-mediated C-H functionalization reactions represent a straightforward approach for such reactions.2 Moreover, only recently, Ackermann et al.,3 Greaney et al.,4 and our group5 reported on light mediated SET reactions or radical formation reactions to achieve such C–H functionalizations, while Baslé et al.6 described a light-mediated C–H activation. Herein, we report on the photocatalytic ortho-alkylation reaction of 2-phenyl pyridines with N-protected maleimides using [Cp*RhCl2]2 as readily available catalyst. Experimental and theoretical studies suggest cyclometalation and migratory insertion to take place in the dark, while photochemical excitation of reaction intermediates is required to facilitate the cleavage of the directing group to enable the protodemetalation to regenerate the catalyst and give the reaction product.7