Photoredox (NN)Mn(I) Catalysed Acceptorless Dehydrogenation: Synthesis of Amides, Aldehydes and Ketones

Abstract

An acceptorless dehydrogenative methodology for the synthesis of amides, aldehydes and ketones from hemiaminal and alcohols in the presence of manganese(I) based photocatalyst is developed. Several aromatic, aliphatic, heterocyclic aldehydes and primary aryl amines as well as secondary alkyl amines were coupled, providing the corresponding amides. The methodology was also extended for dehydrogenation of various alcohols to get the corresponding carbonyls. The proposed catalytic cycle was supported by various control experiments as well as different analytical techniques such as NMR, IR and ESI‐MS.

Switching the hydrogenation selectivity of urea derivatives via subtly tuning the amount and type of additive in the catalyst system

“…58 Thus, the interesting selectivity for hydrogenation of urea derivatives to two-and six-electron reduction products may also be achieved by controlling the fate of a common hemiaminal intermediate (Scheme 4c). 55,[59][60][61][62][63][64] In a basic environment, the process of dehydrogenation of hemiaminal is promoted by the base, as this is a reversible process. 65 The dehydrogenation rate (from hemiaminal to formamide) is greater than the hydrogenation rate (from formamide to hemiaminal), which is conducive to the formation of the formamide product.…”

Iridium Nanoparticles on NiO as Heterogeneous Catalysts for Acceptorless Dehydrogenation of Primary Alcohols with Tunable Product Selectivity

“…Literature survey reveals that AD reactions of alcohol have been mainly accomplished by homogeneous, ligand-based, precious metal catalysts like Ru − and Ir − or selected nonprecious metal catalysts like Co, , Mn, − Ni, − etc. However, despite these advances, the reported homogeneous catalysts suffer from inherent sustainability issues, like use of expensive ligands, lengthy synthesis and purification procedures of ligands and/or complexes, problems in catalyst recovery, efficient recycling, etc.…”