Copper-catalyzed Ullmann condensations are key reactions for the formation of carbon-heteroatom and carbon-carbon bonds in organic synthesis. These reactions can lead to structural moieties that are prevalent in building blocks of active molecules in the life sciences and in many material precursors. An increasing number of publications have appeared concerning Ullmann-type intermolecular reactions for the coupling of aryl and vinyl halides with N, O, and C nucleophiles, and this Minireview highlights recent and major developments in this topic since 2004.

Catalytic C-C, C-N, and C-O Ullmann-type coupling reactions.

140 years ago Adolf von Baeyer proposed the structure of a heteroaromatic compound which revolutionized organic and medical chemistry: indole. After more than a century, indole itself and the complexity of naturally occurring indole derivatives continue to inspire and influence developments in synthetic chemistry. In particular, the ubiquitous presence of indole rings in pharmaceuticals, agrochemicals, and functional materials are testament to the ever increasing interest in the design of mild and efficient synthetic routes to functionalized indole derivatives. This Review emphasizes the achievements in the selective catalytic functionalization of indoles (C-C bond-forming processes) over the last four years.

Catalytic Functionalization of Indoles in a New Dimension

Metal-catalyzed enantioselective allylation, which involves the substitution of allylic metal intermediates with a diverse range of different nucleophiles or S(N)2'-type allylic substitution, leads to the formation of C-H, -C, -O, -N, -S, and other bonds with very high levels of asymmetric induction. The reaction may tolerate a broad range of functional groups and has been applied successfully to the synthesis of many natural products and new chiral compounds.

Metal-catalyzed enantioselective allylation in asymmetric synthesis.

2.3. [4 + 4] Cycloadditions 1058 2.4. Photocycloadditions of Aromatic Compounds 1058 2.4.1. Benzene Derivatives 1058 2.4.2. Condensed Aromatic Compounds 1060 3. Photochemical Rearrangements 1061 4. Cyclizations 1064 4.1. Pericyclizations 1064 4.2. Norrish−Yang Reaction 1066 5. Photochemical Extrusion of Small Molecules 1067 6. Photochemical Electron Transfer 1068 6.1. Photochemical Electron-Transfer Reactions with a Catalytic Sensitizer 1068

Photochemical Reactions as Key Steps in Organic Synthesis

Solvent-free organic synthesis , Solvent-free organic synthesis , کتابخانه دیجیتال جندی شاپور اهواز

Solvent-free organic synthesis

[reaction: see text] Glyoxal bis(N-methyl-N-phenylhydrazone) (1) and its related compounds such as 2-pyridinecarboxaldehyde N-methyl-N-phenylhydrazone (3) were prepared and examined as ligands for the Suzuki-Miyaura cross-coupling reaction of aryl halides and arylboronic acids. We found phosphine-free catalysts, such as Pd(OAc)(2)/hydrazone ligand 1 or 3, to be efficient catalysts for a variety of substrates to produce the coupling products in good yields.

Phosphine-Free Hydrazone−Pd Complex as the Catalyst Precursor for a Suzuki−Miyaura Reaction under Mild Aerobic Conditions

Glyoxal bishydrazones 1 and pyridyl-hydrazone 2b were prepared and examined as a ligand for the Mizoroki−Heck cross-coupling reaction of aryl halides and olefin. We found that PdCl2(MeCN)2/hydrazone ligand 1e was a phosphine-free efficient catalyst system for a variety of substrates to produce the Mizoroki−Heck coupling products in good yields.

Phosphine-free palladium catalyzed Mizoroki-Heck reaction using hydrazone as a ligand.

Phosphine-free palladium catalyzed Mizoroki–Heck reaction using hydrazone as a ligand

Breaking the symmetry of axially chiral N-Aryl-2(1H)-pyrimidinones by spontaneous crystallization.

Palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate (4) with a dimethyl malonate−BSA−LiOAc system and its derivatives has been successfully carried out in the presence of a new chiral hydrazone ligands such as 2-(diphenylphosphino)benzaldehyde SAMP hydrazone (DPPBA-SAMP) (3a) in high yields with high enantioselectives.

Tsutomu Fujita

Papers

Phosphine-Free Hydrazone−Pd Complex as the Catalyst Precursor for a Suzuki−Miyaura Reaction under Mild Aerobic Conditions

Phosphine-free palladium catalyzed Mizoroki-Heck reaction using hydrazone as a ligand.

Phosphine-free palladium catalyzed Mizoroki–Heck reaction using hydrazone as a ligand

Breaking the symmetry of axially chiral N-Aryl-2(1H)-pyrimidinones by spontaneous crystallization.

Palladium-catalyzed allylic alkylation using chiral hydrazones as ligands.