Trifluoromethylchlorosulfonylation of Alkenes: Evidence for an Inner‐Sphere Mechanism by a Copper Phenanthroline Photoredox Catalyst

Abstract

A visible-light-mediated procedure for the unprecedented trifluoromethylchlorosulfonylation of unactivated alkenes is presented. It uses [Cu(dap)2]Cl as catalyst, and contrasts with [Ru(bpy)3]Cl2, [Ir(ppy)2(dtbbpy)]PF6, or eosin Y that exclusively give rise to trifluoromethylchlorination of the same alkenes. It is assumed that [Cu(dap)2]Cl plays a dual role, that is, acting both as an electron transfer reagent as well as coordinating the reactants in the bond forming processes.

Photogenerated Neutral Nitrogen Radical Catalyzed Bifunctionalization of Alkenes

“…The Whitham group has disclosed that benzoyl peroxide (BPO)‐derived benzoyl radical could initiate this process in CHCl 3 heated to reflux . It must also be noted that the Reiser group has reported an unprecedented visible‐light‐driven copper‐catalyzed trifluoromethylchlorosulfonylation of alkenes by using triflyl chloride, without SO 2 extrusion; this reaction provides a new method for carbosulfonylations of alkenes but with only single triflyl chloride used. Quite recently, Zhu et al.…”

Photokatalyse mit sichtbarem Licht: Welche Bedeutung hat sie für die organische Synthese?

“…Mit diesen Katalysatoren kçnnen Perhalogenalkane und a-Carbonylhalogenide (Schema 72, rechts), aber auch elektronenarme Benzylhalogenide [262] mit Alkenen gekuppelt werden (Schema 72, rechts). [264] Das unterschiedliche Verhalten von [265,266] [260,263] WiefürRu II oder Ir III diskutiert (Schema 82), kçnnten die Cu I -katalysierten, durch sichtbares Licht vermittelten ATRA-Prozesse sowohl einem Photoredoxzyklus als auch einem Radikalkettenmechanismus unterliegen.…”

“…Da Sulfonsäurechloride durch [Cu(dap) 2 ]Clkatalysierte photochemische ATRA-Reaktion zwischen unaktivierten Alkenen 284 und CF 3 SO 2 Cl synthetisiert werden kçnnen, [265] wird ein sequentielles Verfahren mçglich, bei dem zwei Alkene über eine Sulfongruppe zu trifluormethylierten b-Hydroxysulfonen 286 führen. Ir IV )stattfindet.…”

“…[265,266] 8.1.5. a-Tri(per)fluoralkylierung von Carbonylverbindungen (sp 3sp 3 ) [265,266] 8.1.5. a-Tri(per)fluoralkylierung von Carbonylverbindungen (sp 3sp 3 )…”

Light on Unsaturated Hydrocarbons – “Gotta Heterofunctionalize Them All”

“…Gratifyingly, high-molecular-weight poly(vinyl acetate) and poly(N-vinylpyrrolidinone) with low dispersities were obtained in bulk polymerizations. The Reiser group [99] studied the trifluoromethylchlorosulfonylation of unactivated alkenes under a photoredox catalytic process mediated by a copper phenanthroline complex {[Cu(dap) 2 ]Cl, 1 mol-%, dap = 2,9-bis(p-anisyl)-1,10-phenanthroline, Scheme 96}. Thus, a wide range of products could be synthesized (517-521) with high regioselectivity for terminal alkenes, whereas mixtures of regioisomers were observed for internal alkenes (Scheme 96).…”