Decarboxylative Iodination Research Articles

Transition-metal-free and solvent-tolerant decarboxylative iodination of aromatic carboxylic acids

Current decarboxylative halogenation methods typically require expensive or toxic transition metal catalysts and have limited solvent compatibility. Herein, we report a novel transition-metal-free and solvent-tolerant decarboxylative iodination method by using iodine monochloride in the presence of potassium phosphate, which are effective to readily available aryl and heteroaryl carboxylic acids, and can be executed in a variety of solvents, including water.

Decarboxylative Iodination of Coumarin‐3‐carboxylic Acids: A Facile Access to 3‐Iodocoumarins

A straightforward protocol for the direct conversion of readily available coumarin‐3‐carboxylic acids to the corresponding 3‐iodocoumarins is described herein. Heating acetonitrile solution of coumarin‐3‐carboxylic acids, molecular iodine and potassium hydrogen phosphate resulted in the decarboxylative iodination of coumarin‐3‐carboxylic acids via radical mechanism. Various electron rich and electron poor coumarin‐3‐carboxylic acids were compatible with the established reaction conditions and consequently afforded the corresponding 3‐iodocoumarins in (46‐93%) reaction yields with minimum purification efforts. The formed products serve as valuable precursors to streamline more complex organic compounds incorporating coumarin core.

Decarboxylative Iodination and Suzuki-Miyaura Coupling Reactions to Access Chiral 3,3'-Diaryl-1,1'-bi-2-naphthols.

An efficient synthesis of the enantiomerically pure 3,3'-bis-arylated BINOLs is accomplished through decarboxylative iodination of the dimethyl ether derivative of BINOL-3,3'-dicarboxylic acid followed by Suzuki-Miyaura coupling using a one-pot protocol. The decarboxylative iodination is effected with the dimethyl ether derivative of BINOL-3,3'-dicarboxylic acid using iodine as a terminal oxidant and the cheaply available K3PO4 as a base under neat conditions. This protocol facilitated the introduction of the aryl group at the 3,3'-position on the binaphthyl system using aryl boronic acid through a palladium-catalyzed Suzuki-Miyaura coupling reaction.

Decarboxylative Iodination of Carboxylic Acids

Key words palladium catalysis - carboxylic acids - aryl iodides - phosphine ligands

Cu-catalyzed decarboxylative iodination of aryl carboxylic acids with NaI: A practical entry to aryl iodides under aerobic conditions

A simple and practical Cu-catalyzed decarboxylative iodination has been well established under aerobic condition, which provides a useful method to synthesize aryl iodides in moderate to good yields with the use of (hetero)aryl carboxylic acids and NaI as starting materials. Thiabendazole has been prepared via a three-step procedure to show synthetic practicability of the protocol.

Visible-Light-Induced Decarboxylative Iodination of Aromatic Carboxylic Acids

A convenient, efficient and practical visible-light-induced decarboxylative iodination of aromatic carboxylic acids has been developed, and the corresponding aryl iodides were obtained in good yields. The method shows some advantages including the use of readily available aromatic carboxylic acids as the starting materials, simple and mild conditions, high efficiency, wide substrate scope and tolerance of various functional groups.

Copper-Catalyzed Decarboxylative Iodination Reaction in the Gas Phase

Copper-Catalyzed Decarboxylative Iodination Reaction in the Gas Phase

Microwave-Assisted Silver-Catalyzed Protodecarboxylation and Decarboxylative Iodination of Aromatic Carboxylic Acids

Carboxylic acids and their derivatives are readily available from both natural and synthetic sources. Apart from being used as direct substrates in the functional transformation, aryl carboxylic acids have found more applications in aromatic functionalization, especially in decarboxylation coupling reactions. Microwave-assisted protodecarboxylation and decarboxylative iodination of aromatic carboxylic acids were achieved with excellent yields in the presence of Ag2CO3 catalyst and K2S2O8. These reactions will be helpful for better understanding of decarboxylation-related coupling reactions and also have the potential of being used as a practical labeling method to synthesize regioselective deuterium and iodine-labelled compounds for chemical, biological, and medicinal research.

Transition-Metal-Free Decarboxylative Iodination: New Routes for Decarboxylative Oxidative Cross-Couplings.

Constructing products of high synthetic value from inexpensive and abundant starting materials is of great importance. Aryl iodides are essential building blocks for the synthesis of functional molecules, and efficient methods for their synthesis from chemical feedstocks are highly sought after. Here we report a low-cost decarboxylative iodination that occurs simply from readily available benzoic acids and I2. The reaction is scalable and the scope and robustness of the reaction is thoroughly examined. Mechanistic studies suggest that this reaction does not proceed via a radical mechanism, which is in contrast to classical Hunsdiecker-type decarboxylative halogenations. In addition, DFT studies allow comparisons to be made between our procedure and current transition-metal-catalyzed decarboxylations. The utility of this procedure is demonstrated in its application to oxidative cross-couplings of aromatics via decarboxylative/C–H or double decarboxylative activations that use I2 as the terminal oxidant. This strategy allows the preparation of biaryls previously inaccessible via decarboxylative methods and holds other advantages over existing decarboxylative oxidative couplings, as stoichiometric transition metals are avoided.

Synthesis of C-14 radiolabeled glucagon receptor antagonist and its use in a human mass balance study.

The synthesis of the radiolabeled glucagon receptor antagonist 1-[14 C] was accomplished based on decarboxylative iodination of acid 2 followed by "reattachment" of 14 C carboxylic function. The method allowed a significant reduction in the number of steps in preparation of the radiolabeled compound. Iodide 4, obtained by the halodecarboxylation, was converted to cyanide 5-[14 C], which was hydrolyzed to provide the radiolabeled acid 2-[14 C]. Coupling with β-alanine fragment and hydrolysis of ester 6-[14 C] completed the synthesis of the target molecule 1-[14 C]. The resulting compound was utilized in a mass balance and metabolism study where hepatic oxidation followed by a trace amount of sulfate conjugation and elimination was the main clearance pathway for 1 in humans.

Synthesis of tunichrome Sp-1

The first total synthesis of the ascidian blood pigment tunichrome Sp-1 is reported, with the modified pentapeptide prepared in a convergent manner using a combination of solid-phase peptide synthesis, Hunsdiecker decarboxylative iodination and Buchwald amidation reaction chemistry. The natural product was shown to exist as a mixture of trans- and cis-prolyl conformers, with the former dominating in a 5:1 ratio.

Convenient synthesis of α,β-unsaturated γ-butyrolactones and γ-butyrolactams via decarboxylative iodination of paraconic acids and β-carboxyl-γ-butyrolactams using 1,3-diiodo-5,5-dimethylhydantoin

A convenient synthetic approach to α,β-unsaturated γ-butyrolactones and α,β-unsaturated γ-butyrolactams is developed. The reaction proceeds via decarboxylative iodination of paraconic acids and β-carboxyl-γ-butyrolactams, employing 1,3-diiodo-5,5-dimethylhydantoin (DIH) under irradiation, followed by dehydroiodination of β-iodo-γ-butyrolactones and γ-butyrolactams providing good yields of α,β-unsaturated γ-butyrolactones and γ-butyrolactams, which are synthetically useful building blocks in organic synthesis.

Functionalization of 3,5,8-trichlorinated BODIPY dyes.

Catalytic hydrogenation of dibenzyl 5-dipyrroketone-2,9-dicarboxylates followed by decarboxylative iodination affords a 2,9-diiododipyrroketone which gives a 2,5,9-trichlorodipyrromethene hydrochloride after nucleophilic addition/elimination, with adventitious chloride to replace the two iodide groups. Treatment with BF3·Et2O gives a 3,5,8-trichloro-BODIPY that readily undergoes regioselective Stille coupling at the 8-position, or homo/mixed couplings at the 3,8- or 3,5- and 8-positions. Stepwise and controlled replacement of the 3,5- and 8-chlorine atoms using Stille reagents results in formation of a completely unsymmetrical trisubstituted BODIPY. Several examples of unsymmetrical BODIPYs were synthesized and characterized using this methodology. Structure features of new BODIPYs are discussed within the context of 14 new X-ray structures, and photophysical parameters of all new BODIPY compounds are reported and discussed.

ChemInform Abstract: Synthesis of Iodocubanes by Decarboxylative Iodination.

AbstractThe cubanecarboxylic acids (I) are consecutively treated with oxalyl chloride and N‐hydroxypyridine‐2‐thione (II) to give the intermediate thiohydroxamates (III) which are cleaved upon irradiation in the presence of 2,2,2‐trifluoroiodoethane to form the iodocubanes (IV).

Synthesis of iodocubanes by decarboxylative iodination

An efficient method is described for the preparation of iodocubanes from the corresponding carboxylic acids utilizing thiohydroxamic ester methodology with 2,2,2-trifluoroiodoethane as the iodide source.