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

Abstract

Direct transformations of readily available amines or amides via C−H bond functionalization could provide a fast route for accessing complex molecules. While various groups have been successfully incorporated into the α position of the nitrogen atom with a photoredox system or C−H bond activation, couplings with functionalized alkyl halides are still very challenging. Herein, we report a direct and convenient protocol for accessing β-amino boronates through the C(sp 3 )−C(sp 3 ) coupling of amides and α-bromoboronates. The mild conditions allow for good functional group tolerance and a broad scope. The application of the method in the latestage modification of complex molecules further demonstrates its great potential in organic synthesis. Mechanistic studies were also conducted, and a catalytic cycle is proposed. KEYWORDS: β-amino boronate, C(sp 3 )−C(sp 3 ) coupling, C−H bond functionalization, metallaphotoredox, nickel

Recent advances of decatungstate photocatalyst in HAT process

“…Xu et al 69 reported an effective method for achieving the C(sp 3 )–C(sp 3 ) coupling of amides and α-bromoboronates to access β-aminoboromonates. The mild conditions, such as visible light, room temperature and absence of strong bases, enable the late-stage transformation of complex molecules and good functional group compatibility.…”