A Direct Palladium-Catalyzed Route for the Synthesis of Benzo[a]carbazoles through Sequential C–C Bond Formation and C–H Bond Functionalization

Aerobic Palladium(II)-Catalyzed 5-endo-trig Cyclization: An Entry into the Diastereoselective C-2 Alkenylation of Indoles with Tri- and Tetrasubstituted Double Bonds

Palladium-Catalyzed Aerobic Dehydrogenative Cross-Coupling of Polyfluoroarenes with Thiophenes: Facile Access to Polyfluoroarene–Thiophene Structure

Synthesis of 2-(Polyfluoroaryl)benzofurans via a Copper(I)-Catalyzed Reaction of 2-(2,2-Dibromovinyl)phenol with Polyfluoroarene

Palladium-Catalyzed Direct ortho-Alkynylation of Aromatic Carboxylic Acid Derivatives - Organic Letters (ACS Publications)

Regioselective Pd-Catalyzed Aerobic Aza-Wacker Cyclization for Preparation of Isoindolinones and Isoquinolin-1(2H)-ones

Pd-Catalyzed Olefination of Perfluoroarenes with Allyl Esters

Rhodium(III)-Catalyzed Intermolecular Direct Amination of Aromatic C–H Bonds with N-Chloroamines

Pd-Catalyzed Olefination of Furans and Thiophenes with Allyl Esters - Organic Letters (ACS Publications)

Copper-Catalyzed Oxidative Alkynylation of Diaryl Imines with Terminal Alkynes: A Facile Synthesis of Ynimines

Direct Arylation of Arene and N-Heteroarenes with Diaryliodonium Salts without the Use of Transition Metal Catalyst

Gold Redox Catalytic Cycles for the Oxidative Coupling of Alkynes

Imparting Catalyst Control upon Classical Palladium-Catalyzed Alkenyl C–H Bond Functionalization Reactions

Gallium(III) Triflate: An Efficient and a Sustainable Lewis Acid Catalyst for Organic Synthetic Transformations

Weak Coordination as a Powerful Means for Developing Broadly Useful C–H Functionalization Reactions

Nickel-Catalyzed C–H/C–O Coupling of Azoles with Phenol Derivatives

Palladium-Catalyzed C3-Benzylation of Indoles

Iron–Copper Cooperative Catalysis in the Reactions of Alkyl Grignard Reagents: Exchange Reaction with Alkenes and Carbometalation of Alkynes

Pd-Catalyzed Oxidative ortho-C–H Borylation of Arenes

Rate-Limiting Step of the Rh-Catalyzed Carboacylation of Alkenes: C–C Bond Activation or Migratory Insertion?

Rhodium(I)-Catalyzed Borylation of Nitriles through the Cleavage of Carbon–Cyano Bonds

Palladium-Catalyzed Oxidative Arylalkylation of Activated Alkenes: Dual C[BOND]H Bond Cleavage of an Arene and Acetonitrile

Iron-Catalyzed C[BOND]H and C[BOND]C Bond Cleavage: A Direct Approach to Amides from Simple Hydrocarbons

Palladium-Catalyzed 2,2,2-Trifluoroethylation of Organoboronic Acids and Esters

The Direct Arylation of Unactivated Arenes with Aryl Halides Catalyzed by a Magnetically Recyclable Fe-Ni Alloy

Snapshot of the Palladium(II)-Catalyzed Oxidative Biaryl Bond Formation by X-ray Analysis of the Intermediate Diaryl Palladium(II) Complex

Ni-Catalyzed Reductive Allylation of Unactivated Alkyl Halides with Allylic Carbonates

DOI: 10.1002/chem.201102984

Silanol as a Removable Directing Group for the PdII-Catalyzed Direct Olefination of Arenes

DOI: 10.1002/chem.201103171

Synthesis of chromans via Pd-catalyzed alkene carboetherification reactions

A new method for the construction of 2-substituted and 2,2-disubstituted chromans via Pd-catalyzed carboetherification reactions between aryl/alkenyl halides and 2-(but-3-en-1-yl)phenols is described. These reactions effect formation of a C–O bond and a C–C bond to afford the chroman products in good yield, and also provide stereoselective access to tricyclic chroman derivatives.

Chem. Commun., 2012, 48, 609-611

Pd-Catalyzed Multiple C[BOND]H Functionalization to Construct Biologically Active Compounds from Aryl Aldoxime Ethers with Arenes

1.  
Chien-Hong Cheng,  DOI: 10.1002/chem.201102996

Nickel- and Cobalt-Catalyzed Direct Alkylation of Azoles with N-Tosylhydrazones Bearing Unactivated Alkyl Groups

Masahiro Miura, DOI: 10.1002/anie.201106825

Transition-Metal-Free Direct Arylation of Anilines

Aryne arylation: A new method of direct arylation is reported for aniline substrates. The reaction uses benzyne to synthesize a variety of aminobiaryls under mild conditions (see scheme), requiring no stoichiometric metalation or transition-metal catalysis. An ene mechanism is implicated, and conveys excellent functional group tolerance relative to metal-mediated processes.

DOI: 10.1002/anie.201106150

Palladium-Catalyzed Oxidative C[BOND]H Bond Acylation of Acetanilides with Benzylic Alcohols

An efficient and clean method to construct CC bonds has been developed via the acylation reaction of acetanilides with benzylic alcohols using tert-butyl hydroperoxide (TBHP) as oxidant catalyzed by palladium acetate in the presence of triflic acid (TfOH). The acylation reactions exhibit excellent reactivities, and up to 95% yield of the corresponding aryl ketone could be obtained under the optimal conditions.

DOI: 10.1002/adsc.201100417

User-Friendly [(Diglyme)NiBr2]-Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through C[BOND]H Bond Cleavages

Lutz Ackermann, DOI: 10.1002/adsc.201100487

Palladium-Catalyzed Selective Synthesis of Naphthalenes and Indenones and Their Luminescent Properties - Chen - 2011 - European Journal of Organic Chemistry - Wiley Online Library

Selective synthesis of functionalized naphthalenes and indenones by palladium-catalyzed cyclization of o-haloacetophenones and terminal alkynes in the presence of a secondary amine is reported. Under a nitrogen atmosphere, the palladium-catalyzed reaction of o-haloacetophenones with terminal alkynes in the presence of wet secondary aminesgenerated 1-(dialkylamino)-3-aryl/alkylnaphthalenes. When the reaction was conducted in air, 1-indenone-3-carbaldehydes were obtained. The synthesized β-arylnaphthalenes 4a–f emit light in a range from 386 to 452 nm with quantum yields from 0.10 to 0.48 in cyclohexane. The absorption and emission efficiency of 4d were finely tuned by the acidity of the environment, and this might be useful in the use of 4d as a fluorescent pH sensor.

Copper-Mediated C–H Activation of 1,3,4-Oxadiazoles with 1,1-Dibromo-1-alkenes Using PEG-400 as a Solvent Medium: Distinct Approach for the Alkynylation of 1,3,4-Oxadiazoles

The direct C–H alkynylation of 1,3,4-oxadiazoles with 1,1-dibromo-1-alkenes has been accomplished by using a combination of CuBr/LiOtBu in PEG-400 (a green solvent) at 80 °C. The products were formed in high yields (73–86 %) in 2 h. No additional ligand or volatile solvent was required and the conversion was ecofriendly.


DOI: 10.1002/ejoc.201101542

Direct amide formation from unactivated carboxylic acids and amines

The direct coupling of unactivated carboxylic acids with amines can be performed in toluene 110 °C in the absence of catalyst. The use of simple zirconium catalysts at 5 mol% loading gave amide formation in as little as 4 h.

Chem. Commun., 2012, 48, 666-668

Oxidation State of Carbon

Calculating oxidation states of different metals should be pretty familiar. Here’s what you do. Take a typical compound – FeCl3, for instance. Treat every bond between the metal and a different atom as if it were an ionic bond. That means the more electronegative elements (like chlorine, say, or oxygen) bear negative charges, and the less electronegative element (such as the metal) bears the positive charge.

If the compound is neutral, the sum of the oxidation states also has to be neutral. (If the compound has a charge, you adjust the oxidation states accordingly so that their sum equals the charge).

Now here’s a fun exercise. Try applying the same rules to carbon.

It’s going to feel a little bit weird. Why? Because there are two key differences.

• First, carbon is often more electronegative (2.5) than some of the atoms it’s bound to (such as H, 2.2). So what do you do in this case?
• Secondly, unlike metal-metal bonds, carbon-carbon bonds are ubiquitous. So how do you deal with them?

Two answers.

1. In a C-H bond, the H is treated as if it has an oxidation state of +1. This means that every C-H bond will decrease the oxidation state of carbon by 1.
2. Any two bonds between the same atom do not affect the oxidation state (recall that the oxidation state of Cl in Cl-Cl (and that of H in H-H) is zero. So a carbon attached to 4 carbons has an oxidation state of zero.

So unlike metals, which are almost always in a positive oxidation state, the oxidation state of carbon can vary widely, from -4 (in CH4) to +4 (such as in CO2). Here are some examples.

(Don’t forget that this is called a “formalism” for a reason. The charge on the carbon isn’t really+4 or –4. But the oxidation state formalism helps us keep track of where the electrons are going, which will come in handy very soon).

Oxidation States of Carbon

Oxidation States of Carbon

O-Allylation of phenols with allylic acetates in aqueous media using a magnetically separable catalytic system

Aqueous and biphasic nitrile hydration catalyzed by a recyclable Ru(II) complex under atmospheric conditions

The palladium-catalyzed desulfitative cyanation of arenesulfonyl chlorides and sodium sulfinates

Mild chemo-selective hydration of terminal alkynes catalysed by AgSbF6

Mathieu Bui The Thuong, André Mann and Alain Wagner 

Chem. Commun., 2012, 48, 434-436

DOI: 10.1039/C1CC12928G

Selective reductive transformations using samarium diiodide-water

Michal Szostak, Malcolm Spain, Dixit Parmar and David J. Procter 

Chem. Commun., 2012, 48, 330-346

DOI: 10.1039/C1CC14252F

Ni(COD)2/PCy3 Catalyzed Cross-Coupling of Aryl and Heteroaryl Neopentylglycolboronates with Aryl and Heteroaryl Mesylates and Sulfamates

Iron-Catalyzed Regioselective Direct Oxidative Aryl–Aryl Cross-Coupling