Ru/Ni Dual Catalytic Desulfinative Photoredox C_sp²–C_sp³ Cross-Coupling of Alkyl Sulfinate Salts and Aryl Halides

Abstract

A mild Ru/Ni dual catalytic desulfinative photoredox C-C cross-coupling reaction of alkyl sulfinate salts with aryl halides has been developed. The optimized catalyst system, consisting of Ru(bpy)Cl, Ni(COD), and DBU, smoothly mediates the coupling of a diverse set of secondary and primary nonactivated alkyl sulfinate salts with a broad range of electron-deficient aryl bromides, electron-rich aryl iodides, and heteroaryl bromides under irradiation with blue light. The procedure is ideal for late-stage introduction of alkyl groups on pharmaceutical intermediates, and the C-C cross-coupling reaction allowed the rapid synthesis of caseine kinase 1δ inhibitor analogues via a parallel medicinal chemistry effort.

Employing Photoredox Catalysis for DNA‐Encoded Chemistry: Decarboxylative Alkylation of α‐Amino Acids

“…In addition, we want to point out that the demonstrated compatibility of DNA with photoredox catalysis bodes well for the adaption of other established photoredox reactions to the specific requirements and limitations of DEL. More specifically, radicals could be conceivably generated from other precursors, for example, oxalates, sulfinates, trifluoroborates, or silicates . Finally, the merger of the presented reaction platform with transition metal catalysis (termed dual catalysis or metallaphotoredox catalysis) would further expand the current scope of DNA‐compatible chemistries.…”

Alkyl Carbon–Carbon Bond Formation by Nickel/Photoredox Cross‐Coupling

“…[10] Subsequently,m ultiple strategies for C(sp 3 )r adical generation have been developed. Some approaches rely on redox-active groups,s uch as alkyltrifluoroborates,c arboxylates,b is(catecholato)silicates, and 1,4-dihydropyridines,t oa chieve programmed reactivity ( Figure 3), and others utilize the innate reactivity of substrates (via hydrogen or halogen atom transfer) to generate alkyl radicals.R adicals originating from the oxidation of sulfinate salts, [21] xanthates, [22] and a-silylamines [23] have also been employed in this cross-coupling strategy,a lthough they are not discussed in this Minireview.…”

Alkyl‐C‐C‐Bindungsbildung durch Nickel/Photoredox‐Kreuzkupplung

“…Andere nutzen die inhärente Reaktivitätv on Substraten (über Wasserstoff-oder Halogenatomtransfer) zur Erzeugung von Alkylradikalen. Es wurden auch Radikale aus der Oxidation von Sulfinatsalzen, [21] Xanthaten [22] und a-Silylaminen [23] in dieser Kreuzkupplungsstrategie verwendet, obgleich sie in diesem Kurzaufsatz nicht diskutiert werden.…”