Visible-Light-Promoted Dual Photoredox/Nickel-Catalyzed Chemoselective Reduction of Secondary and Tertiary Amides with Hydrosilanes in the Presence of an Ester

Abstract

We report a one-step procedure to selectively reduce secondary and tert-amides to their corresponding amine derivatives in the presence of an ester. This was achieved via the synergistic combination of a photoredox, a nickel catalytic system, and phenyl silane as a reductant in the presence of blue light-emitting diode light (455 nm) at room temperature. Further, this mild light-promoted dual metallaphotoredox catalytic system was also successful in selectively reducing a lactam to the cyclic amines, without affecting the ester moiety present in the molecules.

TBAT-Catalyzed Deoxygenative Reduction of Tertiary Amides to Amines

“…14 Recently, our team has developed a dual photoredox/nickel-catalytic system for the chemoselective reduction of amides. 15 Despite the progress of hydrosilylations that have been done well until now, most of these methods have used expensive metals and operate at high temperatures. These limitations have encouraged us to explore the development of a metal-free protocol under mild conditions to reduce amides to amines.…”

“…In addition to this, metal-free protocols have also emerged to tune reactivity by using organocatalysts such as B­(C 6 F 5 ) 3 , , Tf 2 O, Et 3 B, NaEt 3 BH, BPh 3 , frustrated Lewis pairs (FLP), and TBAF. , The use of bases like K t OBu, KOH, and Cs 2 CO 3 are also reported for hydrosilylation reactions . Recently, our team has developed a dual photoredox/nickel-catalytic system for the chemoselective reduction of amides . Despite the progress of hydrosilylations that have been done well until now, most of these methods have used expensive metals and operate at high temperatures.…”