Iridium(I)-Catalyzed Alkylation Reactions To Form α-Alkylated Ketones

Abstract

A highly effective and green procedure for the formation of α-alkylated ketones has been disclosed via the reaction of primary alcohols with secondary alcohols and ketones by using [IrCl(COD)(NHC)] complexes as a catalyst. Various α-alkylated ketones were obtained in high yields from the alkylation of alcohol with alcohol and ketone with alcohol through a borrowing hydrogen reaction by using 0.05-0.5 mol % iridium(I) and a catalytic amount of KOH (5-10 mol %) as the base under air atmosphere and within very short reaction times.

Choline Chloride-Based Deep Eutectic Systems in Sequential Friedländer Reaction and Palladium-Catalyzed sp3 CH Functionalization of Methyl Ketones

“…It is noteworthy to emphasize that, in all cases, byproduct-reductive products, ketals, and hemiketals formation were not observed. The reaction outcomes are identical comparing to earlier reports using iridium and 11,12,60,61 ruthenium, 23,62 in organic solvents (Table 7).…”

“…Initially acetophenone 1a reacted with benzyl alcohol 2a , utilizing Pd(PPh 3 ) 4 , xantphos, and KO t Bu in ChCl–oxalic acid—DES at 80 °C for 6 h, to give 80% yield (Table 1, entry 22). It is evident that in the earlier reports, 11,12,23,58−60 a volatile and toxic solvent has been utilized, including toluene, 1,4-dioxane, t -amyl alcohol, tetrahydrofuran, N -methyl-2-pyrrolidone, and so forth. However, in the present work to avoid toxic organic solvents, the DES made from cheap and biodegradable choline chloride has been utilized (Table 2).…”

Ir(NHC)‐Catalyzed Synthesis of β‐Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure

“…Various homogeneous transition‐metal catalysts have been reported for transition metal‐catalyzed β‐alkylation of alcohols via the BH strategy. Iridium, ruthenium, palladium, iron, copper, manganese, cobalt, and nickel catalysts were employed for cross‐coupling of secondary and primary alcohols [6–37] . For the condensation of primary alcohols (Guerbet reaction), iridium, rhodium, ruthenium, and manganese catalysts were employed [5,38–49] .…”

“…For the condensation of primary alcohols (Guerbet reaction), iridium, rhodium, ruthenium, and manganese catalysts were employed [5,38–49] . Based on studies of carbene‐ligand‐modified iridium catalysts, the electronic and steric properties of NHC ligands affect the catalytic activities of iridium catalysts forming Ir−H from alcohols, e. g., transfer hydrogenation and β‐alkylation of alcohols [6–10,50–52] . In this study, we employed mono‐ and bimetallic Ir(NHC) catalysts for the synthesis of high molecular weight branched alcohols through the Guerbet reaction and inter‐ and intramolecular coupling of secondary and primary alcohols.…”

Manganese(I)-Catalyzed Cross-Coupling of Ketones and Secondary Alcohols with Primary Alcohols

“…In general, this catalytic alkylation of ketones using alcohols is implemented using noble metals such as ruthenium, 5 palladium, 6 osmium, 7 iridium, 8 etc. Accordingly nonprecious first-row transition metals 9 have drawn much attention.…”