Decarboxylative Aminomethylation of Aryl‐ and Vinylsulfonates through Combined Nickel‐ and Photoredox‐Catalyzed Cross‐Coupling

Abstract

A mild approach for the decarboxylative aminomethylation of aryl sulfonates by the combination of photoredox and nickel catalysis through C-O bond cleavage is described for the first time. A wide range of aryl triflates as well as aryl mesylates, tosylates and alkenyl triflates afford the corresponding products in good to excellent yields.

Visible‐Light Photocatalysis as an Enabling Tool for the Functionalization of Unactivated C(sp3)‐Substrates

“…[1] Over the past decade, visible-light photocatalysis has emerged as one of the most dynamic and powerful synthetic manifolds in today's synthetic chemistry landscape. [2][3][4][5][6][7][8][9][10][11][12][13][14] This is initial studies focused largely on the functionalization of stabilized radical intermediates, over the past few years significant efforts have been directed towards the functionalization of challenging unactivated radical precursors. In this review we summarize the recent developments in the use of visible-light photocatalysis for the functionalization of unactivated C(sp 3 )-substrates.…”

Aminomethylation of Aryl Halides Using α-Silylamines Enabled by Ni/Photoredox Dual Catalysis

“…This is in stark contrast to the success encountered by MacMillan, Doyle, Rueping, and others when using dialkylanilines, where carbon-centered radicals are generated by decarboxylative fragmentation, hydrogen atom transfer (HAT), or deprotonation. 10–12 The success incurred with these scaffolds can be attributed to their relatively low oxidation potentials coupled with α-amino radical stabilization. However, the same rationale for the successes with these systems ultimately highlight their restrictions, namely that only activated amines can succumb to visible light activation.…”

Der “Persistent Radical Effect” in der organischen Chemie

“…fragmentieren (Abbildung a). Diese Radikale werden von der Nickel(II)‐Spezies abgefangen, um die Kreuzkupplung mit Aryl‐, Alkylhalogeniden, Acylchloriden oder Aryltrilfaten einzugehen. Mit Sulfinaten als Radikalvorläufer wird das durch SET‐Oxidation erhaltene Sulfinyl‐Radikal direkt durch die Ni II ‐Spezies abgefangen, wodurch nach reduktiver Eliminierung eine C‐S‐Bindung ausgebildet wird …”