Synthesis of Chiral Amines by C–C Bond Formation with Photoredox Catalysis

Abstract

Chiral amines are key substructures of biologically active natural products and drug candidates. The advent of photoredox catalysis has changed the way synthetic chemists think about building these substructures, opening new pathways that were previously unavailable. New developments in this area are reviewed, with an emphasis on C–C bond constructions involving radical intermediates generated through photoredox processes.

Dual Nickel/Photoredox‐Catalyzed Synthesis of N‐formyl N,N’‐Diaryl Ethylenediamines via Multiple C−N/C−C Coupling of Nitroarenes with Trimethylamine

“…Several control experiments were conducted to evaluate the effect of catalysts and reagents on the amination reaction. When PC3 was omitted, the reaction did not proceed (Table S2, Supporting Information), indicating the necessity of photocatalyst to initiate the photo‐induced single‐electron transfer events, such as the photoreduction of nitroarene [17] and the photooxidation of trimethylamine, [13c,d] to enable subsequent bond formation reactions. Likewise, in the absence of or Ni/ L1 complex, no reaction occurred as well (Table S6, Supporting Information), suggesting that the Ni catalyst likely mediates the C−C bond coupling reaction [21] to construct the ethylenediamine skeleton.…”

Direct Synthesis of β-Amino Boronates via Amide α-C–H Bond Activation and C(sp3)–C(sp3) Coupling under Dual Ni/Photoredox Catalysis

“…The functionalization of amines through the direct transformation of the N α-C–H bond has emerged as a powerful synthetic approach for accessing a range of complex molecules that are of great importance but are challenging to obtain using conventional methods, especially when starting from readily available materials . This protocol has been greatly promoted in recent years, particularly with the development of transition metal (TM) catalysis and radical chemistry, which enables the smooth formation of various types of new carbon–carbon bonds, such as C–H bond arylation, alkenylation, alkynylation, and acylation (Scheme A).…”