Gold-Catalyzed Regiospecific Hydration of N-Tosyl Propargylic Amines

The regioselective Wacker oxidation of internal allylamines: synthesis of functionalized and challenging β-amino ketones

A convenient and general protocol for the palladium-catalysed oxidation of internal allylamine derivatives to β-amino ketones is reported. The transformation occurs at room temperature and shows a wide substrate scope as well as high functional group and N-protecting group tolerance. We also describe potential applications of the method, e.g., the synthesis of bioactive molecules or simple transformations of selected β-amino ketones into other interesting building blocks.

Alkynyl Borrowing: Silver-Catalyzed Amination of Secondary Propargylic Alcohols via C(sp3)-C(sp) Bond Cleavage

The silver-catalyzed alkynyl borrowing amination of secondary propargyl alcohols via C(sp³)-C(sp) bond cleavage has been developed. This new strategy was based on the β-alkynyl elimination of propargyl alcohols and alkynyl as the borrowing subject. This alkynyl borrowing amination featured high atom economy, wide functional group tolerance, and high efficiency.

Photoredox-mediated N-centered radical addition/semipinacol rearrangement for the convenient synthesis of β-amino (spiro)cyclic ketones

A photoredox-mediated N-centered radical addition/semipinacol rearrangement cascade of cycloalkanol-substituted 1H-indenes or styrenes with N-arylsulfonyl protected 1-aminopyridinium salts for the efficient synthesis of β-amino (spiro)cyclic ketones is presented.

Experimental and computational evidence on gold-catalyzed regioselective hydration of phthalimido-protected propargylamines: an entry to β-amino ketones

The results of our investigations on the Au-catalyzed regioselective hydration reaction of both alkyl- and aryl-substituted N-propargyl phthalimides directed to the selective formation of the corresponding β-phthalimido ketones are described. Experimental data, in particular the observed regioselectivity, have been qualitatively supported by quantum-chemical calculations carried out on model systems in the framework of Density Functional Theory (DFT) followed by quantum theory of atoms in molecules (QTAIMS). Our results suggest that the electronic features of the initial adduct between the propargyl triple bond and the Au(i) catalyst, in particular the character of the gold-triple bond interaction, are essential for the observed regioselectivity. Other effects, such as the presence of the solvent and the formation of a H-bond between the water molecule and the phthalimido moiety, although apparently irrelevant for the regioselectivity, have proven to be kinetically and catalytically rather important.

Metal-Free Carbonyl-Assisted Regioselective Hydration of Alkynes: An Access to Dicarbonyls

Metal-free regioselective hydration of o-alkynylaldehydes with the assistance of neighboring carbonyl oxygen is disclosed. The developed protocol provides a facile route to synthesize a series of multisubstituted carbonyl containing scaffolds that enable the potential application toward the synthesis of highly diversified 5-azaindoles. γ-Carbolines and 2,8-diazacarbazoles can also be accessed directly without isolating the dicarbonyl compounds. The developed methodology is operationally simple and environment-friendly, tolerates a wide variety of functional groups, and is applicable toward large scale synthesis.

Gold-Catalyzed Hydrophenoxylation of Propargylic Alcohols and Amines: Synthesis of Phenyl Enol Ethers

A practical method for the synthesis of phenyl enol ethers is reported. The combination of a gold(I) catalyst and potassium carbonate selectively mediates the addition of phenols to propargylic alcohols/amines in a chemo-, regio-, and stereoselective fashion in high yield. The resulting enol ethers are formed exclusively with a Z-configuration and can be obtained from a wide array of phenols and propargylic alcohols or amines with the reaction showing excellent functional group tolerance.