Pyrazole based palladacycles for the synthesis of β-aminoketones by redox coupling of allyl alcohols and anilines.

Herein, we report the synthesis of β-aminoketones by oxidative coupling of allyl alcohols at room temperature using a pyrazole based palladacycle and BINOL-phosphoric acid system. This method avoids the use of any base, external oxidant, and additive. The reaction of -anisidine and 1-penten-3-ol under the optimized conditions using isolated palladacycle-BINOL-phosphoric acid produced the desired product in 24 h, which suggests that the active species involved in this reaction is the palladacycle-BINOL-phosphoric acid.

Ligand-Controlled Ruthenium-Catalyzed Borrowing-Hydrogen and Interrupted-Borrowing-Hydrogen Methodologies: Functionalization of Ketones Using Methanol as a C1 Source.

Herein we report simple, highly efficient, and phosphine-free N,C-Ru and N,N-Ru catalysts for ligand-controlled borrowing-hydrogen (BH) and interrupted-borrowing-hydrogen (I-BH) methods, respectively. This protocol has been employed on a variety of ketones using MeOH as a green, sustainable, and alternative C1 source to form a C-C bond through the BH and I-BH methods. Reasonably good substrate scope, functional group tolerance, and good-to-excellent yields at 70 °C are the added highlights of these methodologies.

Palladium-Mediated Tandem Isomerization-Methylenation of Allyl Alcohols: One-Pot Synthesis of 1,5-Diketones.

A novel methodology for the synthesis of 1,5-diketones through a one-pot isomerization-methylenation of a variety of allylic alcohols has been established for the first time. This methodology utilizes commercially available palladium acetate and easily accessible BINOL phosphoric acid. Both isomerization of allylic alcohol and oxidation of methanol occurred through a single catalyst.

Cobalt(II)porphyrin-Mediated Selective Synthesis of 1,5-Diketones via an Interrupted-Borrowing Hydrogen Strategy Using Methanol as a C1 Source.

A novel cobalt(II)porphyrin-mediated acceptorless dehydrogenation of methanol is reported for the first time. This methodology has been applied for the coupling of a variety of ketones with methanol to produce 1,5-diketones along with H and HO as the environment friendly byproducts. This paradigm was also demonstrated for a one-pot synthesis of substituted pyridines using a sequential addition protocol where the 1,5-diketones were generated in situ.

Palladium mediated one-pot synthesis of 3-aryl-cyclohexenones and 1,5-diketones from allyl alcohols and aryl ketones.

One-pot synthesis of Robinson annulated 3-aryl-cyclohexenones from allyl alcohols and ketones using palladium is reported. Long chain aliphatic or aryl substitutions at the C1 position of allyl alcohol result in the formation of 1,5-diketone products. This simple one-pot method avoids the use of highly electrophilic vinyl ketones.

Palladacycle-Phosphine Catalyzed Methylation of Amines and Ketones Using Methanol.

Methylation of amines and ketones with palladacycle precatalyst has been performed using methanol as an environmentally benign reagent. Various ketones and amines undergo methylation reaction to yield monomethylated amines or ketones in moderate to good isolated yields. Moreover, this protocol was tested for the chemoselective methylation of 4-aminobenzenesulfonamide.