Trifluormethylchlorsulfonylierung von Alkenen – Hinweise auf einen Innensphärenmechanismus eines Kupferphenanthrolin‐Photoredoxkatalysators

Abstract

Die Trifluormethylchlorsulfonierung von Alkenen gelingt durch die Kombination von sichtbarem Licht und [Cu(dap)2]Cl als Photoredoxkatalysator. Im Gegensatz dazu katalysieren [Ru(bpy)3]Cl2, [Ir(ppy)2(dtbbpy)]PF6 oder Eosin Y eine Trifluormethylchlorierung. [Cu(dap)2]Cl spielt in diesem Prozess eine zweifache Rolle: Einerseits agiert es als Elektronentransferreagens, andererseits koordiniert es die Reagentien für die Bindungsbildung.

Photoredox Catalysis in C–S Bond Construction: Recent Progress in Photo‐Catalyzed Formation of Sulfones and Sulfoxides

“…Later, Reiser developed a visible light‐mediated trifluoromethylchlorosulfonylation of unactivated alkenes with triflyl chloride under the catalysis of [Cu(dap) 2 ]Cl [dap=2,9‐bis( para ‐anisyl)‐1,10‐phenanthroline] . In most cases, the electron transfer to triflyl chloride with ruthenium, iridium complexes or Eosin Y as photocatalyst is accompanied with SO 2 extrusion and gives trifluoromethyl‐substituted product ,.…”

Mononuclear and dinuclear heteroleptic Cu(I) complexes based on pyridyl-triazole and DPEPhos with long-lived excited-state lifetimes

“…[15][16][17][18] The pioneering work of Sauvage and co-workers with Cu(dap)2Cl [19] as photoredox catalyst was published in 1987, [20] but apart from some contemporary publications, [21] only recently have Cu(I) complexes been applied as photoredox catalysts or photosensitizers (PS). [22][23][24][25][26][27][28][29][30][31][32] In artificial photosynthesis [33,34] the photosensitizer absorbs the luminous radiation and transfers the energy to a catalyst, which then activates the small molecule (usually either water or carbon dioxide). The characteristics that a PS should have are the following: good absorption in the visible light region, long-lived excited state, and high stability.…”

Synthesis of Trifluoromethylated Sultones from Alkenols Using a Copper Photoredox Catalyst

“…21 [Cu(dap) 2 ]Cl was identified as unique catalyst which in contrast to other photoredox catalysts 23 gives rise to net addition of a trifluoromethyl and a chlorosulfonyl group to the alkene. Expanding the scope of this transformation, we report herein the one-step visible light mediated synthesis of α-substituted trifluoromethylated sultones from α,ω-alkenols.…”

“…Following our interest in photocatalysis 20 and especially the application of environmental-benign copper-complexes 21,22 for visible light photoredox catalysis, we have investigated the copper catalyzed visible-light reaction of CF 3 SO 2 Cl with terminal alkenes. 21 [Cu(dap) 2 ]Cl was identified as unique catalyst which in contrast to other photoredox catalysts 23 gives rise to net addition of a trifluoromethyl and a chlorosulfonyl group to the alkene.…”