Visible-light-induced 3d transition metal-catalysis: A focus on C–H bond functionalization

Organometallic catalysis under visible light activation: benefits and preliminary rationales

“…Köhler and co-workers demonstrated that visible-light can be used to enhance Mizoroki-Heck reactions between bromobenzene (6) and styrene (7) to give stilbene (8) (Scheme 2) [11]. Here, light accelerates the reduction of the Pd(II) pre-catalyst 9 by sodium formate (HCOONa) to the active Pd(0) species 10, as evidenced by NMR and UV/ Vis spectroscopic studies.…”

“…The ability to harness visible light to access energy transfer reactivity is another emerging field of profound impact in organic synthesis [4,5]. Recently, further developments have revealed the ability of light to interact directly with organometallic complexes involved in the cross-coupling catalytic cycle (rather than the photocatalyst) inducing novel and unique bond-breaking/forming reactivities, thereby expanding the diversity of possible chemical transformations [6,7]. In this context, light can be used to induce or accelerate a reaction step.…”

Visible‐Light‐Induced, Single‐Metal‐Catalyzed, Directed C−H Functionalization: Metal‐Substrate‐Bound Complexes as Light‐Harvesting Agents

“…One strategy envisages the development of state-of-the-art catalysts and reactive reagents that can be used under ambient conditions (Scheme 1b). [2,3,5,[24][25][26][27][28][29] Further alternatives lie in the use of catalysts based on earth-abundant metals [30][31][32] or the use of electrochemical or photocatalytic methods that rely on the redox chemistry of substrates and/or catalysts. [22,[33][34][35][36][37] These strategies are not in the focus of this Minireview and the reader is referred to recent review articles on these topics.…”

“…A conceptually distinct, recent approach builds on the photochemical properties of metal complexes, which are often intensely colored, absorb visible light, and can be used as both the photosensitizer and catalyst without the need for an exogeneous photosensitizer. [30,31,[38][39][40] In the context of CÀ H functionalization reactions, this approach involves a single transition-metal catalyst that is capable of both converting photonic energy into usable chemical energy and enabling key elementary steps to allow the CÀ H functionalization of organic molecules.…”

Photoinduced palladium-catalyzed 1,2-difunctionalization of olefins

“…The use of visible light as a source of energy plays a key role in the development of sustainable organic synthesis methods and the reduction of environmental and ecologic footprint of chemical synthesis. [1][2][3][4][5][6][7][8] For this purpose, photosensitizers find wide-spread application to convert photonic energy into chemical energy via photoexcitation of intensely colored dyes. More recently, archetypal transition metal catalysts for cross-coupling or C-H activation were identified as suitable sensitizers to enable photocatalysis with a single metal catalyst, which exhibits a dual function as photosensitizer and as catalyst for C-C or C-X bond formation at the same time.…”