Late transition metal-catalyzed hydroamination and hydroamidation.

Update 1 of: Synthesis and Functionalization of Indoles Through Palladium-Catalyzed Reactions

Transition metal catalyzed denitrogenative transannulation of a triazole ring has recently received considerable attention as a new concept for the construction of diverse nitrogen-containing heterocyclic cores. This method allows a single-step synthesis of complex nitrogen heterocycles from easily available and cheap triazole precursors. In this Minireview, recent progress of the transition metal catalyzed denitrogenative transannulation of a triazole ring, which was discovered in 2007, is discussed.

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Transition-Metal-Catalyzed Denitrogenative Transannulation: Converting Triazoles into Other Heterocyclic Systems

Indoles are the most abundant heterocycles in biologically active natural products, pharmaceuticals, agrochemicals, and are relevant substructures in functional materials. As a result, the development of methodologies that enable the synthesis of these compounds is continuously demanded. This review summarizes most recent and relevant approaches towards the preparation of this prevalent structural motif.

Recent advances in indole syntheses: New routes for a classic target

A survey highlighting the most recent palladium catalytic systems produced and their performances for progress in direct synthesis of indole backbones by heterocarbocyclization of reactive substrates is provided The discussion is developed in relation with the principles of sustainable chemistry concerning atom and mass economy In this respect, the general convergent character of the syntheses is of particular interest (one-pot, domino, cascade or tandem reactions), and the substrates accessibility and reactivity, together with the final waste production, are also important This critical review clearly indicates that the development of ligand chemistry, mainly phosphines and carbenes, in the last few decades gave a significant impetus to powerful functionalization of indoles at virtually all positions of this ubiquitous backbone (118 references)

Progress in palladium-based catalytic systems for the sustainable synthesis of annulated heterocycles: a focus on indole backbones.

Palladium-catalyzed indolization of N-aroylbenzotriazoles with disubstituted alkynes.

Copper-Catalyzed Rearrangement of (Z)-Propynal Hydrazones via N−N Bond Cleavage

A variety of β-aminoacrylonitriles is prepared in the reaction, catalyzed by Cu(OAc)2, followed by the Z/E-isomerization, induced by AcOH.

Copper-Catalyzed Rearrangement of (Z)-Propynal Hydrazones via N—N Bond Cleavage.

The palladium-catalyzed denitrogenative indolization of N-aroylbenzotriazoles 1 and internal alkynes 2 produced the corresponding polysubstituted indoles 3 in good to high yields. For example, the reaction of 5,6-dimethyl-1-[4-(trifluoromethyl)benzoyl]benzotriazole (1j) with 6-dodecyne (2a), 4-octyne (2b), and diphenylacetylene (2f) in the presence of 10 mol % of Pd(PPh3)4 without solvent at 130 °C gave the corresponding indoles 3i, 3l, and 3p in 74, 71, and 41% yields, respectively. In the present reaction, the aroylbenzotriazole acts as a synthetic equivalent of a 2-haloanilide in Larock’s indole synthesis.

Naozumi Shiraiwa

Papers

Palladium-catalyzed indolization of N-aroylbenzotriazoles with disubstituted alkynes.

Copper-Catalyzed Rearrangement of (Z)-Propynal Hydrazones via N−N Bond Cleavage

Copper-Catalyzed Rearrangement of (Z)-Propynal Hydrazones via N—N Bond Cleavage.

Palladium‐Catalyzed Indolization of N‐Aroylbenzotriazoles with Disubstituted Alkynes.