Photo-Induced Ruthenium-Catalyzed C-H Arylation Polymerization at Ambient Temperature.

Transition metal-catalyzed C-H arylation polymerization (CHAP) is an attractive tool for constructing π-conjugated polymers in a sustainable manner. However, the existing methods primarily rely on palladium catalysis, which usually entails harsh reaction conditions and branching/cross-linking. Here we report the first example of an ambient-temperature ruthenium-catalyzed C-H arylation polymerization induced by visible light irradiation. The present polymerization can produce various meta- and para-linked polymers in excellent yields with high molecular weights. The remarkable feature of our mild reaction platform is represented by high chemoselectivity, leading to polymers that are otherwise inaccessible under conventional reaction conditions at high temperatures.

Polymer up-cycling by mangana-electrocatalytic C(sp3)-H azidation without directing groups.

The chemical up-cycling of polymers into value-added materials offers a unique opportunity to place plastic waste in a new value chain towards a circular economy. Herein, we report the selective up-cycling of polystyrenes and polyolefins to C(sp3)-H azidated materials under electrocatalytic conditions. The functionalized polymers were obtained with high retention of mass average molecular mass and high functionalization through chemo-selective mangana-electrocatalysis. Our strategy proved to be broadly applicable to a variety of homo- and copolymers. Polyethylene, polypropylene as well as post-consumer polystyrene materials were functionalized by this approach, thereby avoiding the use of hypervalent-iodine reagents in stoichiometric quantities by means of electrocatalysis. This study, hence, represents a chemical oxidant-free polymer functionalization by electro-oxidation. The electrocatalysis proved to be scalable, which highlights its unique feature for a green hydrogen economy by means of the hydrogen evolution reaction (HER).

Rhodaelectro-catalyzed chemo-divergent C-H activations with alkylidenecyclopropanes for selective cyclopropylations.

Herein, we report on selectivity control in C-H activations with alkylidenecyclopropanes (ACPs) for the chemo-selective assembly of cyclopropanes or dienes. Thus, unprecedented rhodaelectro-catalyzed C-H activations were realized with diversely decorated ACPs with a wide substrate scope and electricity as the sole oxidant.

Chemodivergent manganese-catalyzed C-H activation: modular synthesis of fluorogenic probes.

Bioorthogonal late-stage diversification of amino acids and peptides bears enormous potential for drug discovery and molecular imaging. Despite major accomplishments, these strategies largely rely on traditional, lengthy prefunctionalization methods, heavily involving precious transition-metal catalysis. Herein, we report on a resource-economical manganese(I)-catalyzed C-H fluorescent labeling of structurally complex peptides ensured by direct alkynylation and alkenylation manifolds. This modular strategy sets the stage for unraveling structure-activity relationships between structurally discrete fluorophores towards the rational design of BODIPY fluorogenic probes for real-time analysis of immune cell function.