Iridium-Catalyzed Reductive Nucleophilic Addition to Secondary Amides

Abstract

An iridium-catalyzed reductive nucleophilic addition to secondary amides is reported. After the iridium-catalyzed reduction, the resulting imines can undergo the Strecker reaction, the Mannich reaction, allylation, and [3 + 2]-cycloaddition. The method shows high chemoselectivity in the presence of other functional groups such as methyl ester.

Deoxygenation of Primary Amides to Amines with Pinacolborane Catalyzed by Ca[N(SiMe3)2]2(THF)2

“…Nevertheless, this procedure not only raises significant safety concerns and environmental issues but also suffers from the lack of selectivity in the presence of various functional groups. As amide hydrogenations are widely processed along with elevated pressure and temperature at the cost of expensive metal catalysts, a catalytic hydrogenation strategy should be well-received for its atom economy (Scheme b). , Recent progress shows that catalytic hydrosilylation is a promising method for transforming amides to amines; however, it requires an excessive amount of expensive and air-sensitive silanes (Scheme c). − It is, therefore, necessary and meaningful to develop new methodology to address the challenges in amide reduction.…”

Asymmetric Spirocyclization Enabled by Iridium and Brønsted Acid-Catalyzed Formal Reductive Cycloaddition

“…36 Alternatively, the seminal catalytic reductive functionalization of amides with silane reagents has emerged. IrCl(CO)(PPh 3 ) 2 [37][38][39][40][41][42][43][44] and Mo(CO) 6 [45][46][47] have been developed as effective catalysts for the hydrosilylation of amides, thus diversifying the reaction of reductive functionalization of amides…”

“…The development of an asymmetric reductive transformation of amide to access enantiomerically pure products remains highly desirable. Since an O-silylated hemiaminal is the proposed intermediate of hydrosilylation of amides, [37][38][39][40][41][42][43][44] we hypothesized that the desilanolation of hemiaminal silyl ether I in the presence of a chiral phosphoric acid would initiate a formal cycloaddition reaction with exocyclic enamides (Scheme 1c). As such, a 1-azaspirocycle framework would be constructed accordingly.…”

Recent advances in the iron‐catalysed multicomponent reactions

“…The very first multicomponent reaction involves the three‐component reaction of aldehyde, hydrogen cyanide and ammonia used for the synthesis of α‐amino acids, and the reaction is called Strecker reaction. [ 4,5 ] Later, many other reactions were also reported using multicomponent strategies, viz. Hantzsch dihydropyridine synthesis, [ 6,7 ] Biginelli reaction, [ 8,9 ] Passerini reaction, [ 10,11 ] Kabachnik‐Fields reaction, [ 12,13 ] Ugi reaction, [ 14,15 ] Gröbcke‐Blackburn‐Bienaymé reaction [ 16 ] etc.…”