Ruthenium‐Catalyzed Three‐Component Alkylation: A Tandem Approach to the Synthesis of Nonsymmetric N,N‐Dialkyl Acyl Hydrazides with Alcohols

Abstract

The borrowing hydrogen strategy has been applied in the synthesis of nonsymmetric N,N‐dialkylated acyl hydrazides via a tandem three‐component reaction catalyzed by a phosphine free diaminocyclopentadienone ruthenium tricarbonyl complex. This strategy represents the first direct one‐pot approach to nonsymmetric functionalized acyl hydrazides. Different aromatic acyl hydrazides underwent dialkylation with a variety of primary or secondary alcohols and methanol or ethanol as alkylating agents in mild reaction conditions and good yields. Deuterium labelling experiments suggested that the primary or secondary alcohol was the hydrogen source in this tandem process. DFT calculations show that the combination of the tandem mixed product cannot be perfectly explained neither structurally nor electronically, but might be dependent of the physical state of the aldehyde or ketone intermediate (gaz vs. liquid) at the reaction temperature.

Knölker Iron Catalysts for Hydrogenation Revisited: A Nonspectator Solvent and Fine-Tuning

“…However, when it comes to CN bonds, hydrogenation is still a challenge for homogeneous catalysis . Noble metals such as rhodium, palladium, ruthenium, or iridium were initially reported for the reductive amination of carbonyl compounds, using molecular hydrogen, formic acid, transfer hydrogenation, or borrowing hydrogen. , Among all catalysts discovered, ruthenium became the most extensively used metal . In particular, Noyori and Shvo catalysts (represented in Scheme ) have been used for the hydrogenation of the previously mentioned polar functional groups …”

Synthesis of Acyl Hydrazides from Carboxamides and Hydrazine Hydrate Under Metal‐Free Conditions at Room Temperature

“…Additional references cited within the Supporting Information. [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] Table 6. Transamidation of different N-tosyl α-ketoamides with benzylamine.…”

Expedient tandem dehydrogenative alkylation and cyclization reactions under Mn(i)-catalysis

“…11 Very recently, the research group of Renaud and Poater reported a diaminocyclopentadienone ruthenium tricarbonyl complex-catalyzed synthesis of mono- or dialkylated acyl hydrazide compounds using the borrowing hydrogen strategy. 12…”