Selective Mono- and Dialkynylation of 1-Fluoro-2,2-diiodovinylarenes Using Pd-Catalyzed Decarboxylative Coupling Reactions

Selective Synthesis of (Z)- and (E)-β-Fluoro-α,β-Unsaturated Amides Using Palladium-Catalyzed Aminocarbonylation

The selective synthesis of (Z)- and (E)-β-fluoro-α,β-unsaturated amides via the palladium-catalyzed aminocarbonylation of 1-fluoro-2,2-diiodovinylarenes is described in the present study. Using {Pd(allyl)Cl}2 as a catalyst and DBU as a base in DMF, the primary product is (Z)-isomers. Conversely, the use of a Xantphos ligand along with {Pd(allyl)Cl}2 and Et3N as the bases in 1,4-dioxane leads to the selective formation of (E)-isomers. Notably, 1-fluoro-2,2-diiodovinylarenes with various substituents on the phenyl ring react with various secondary amines, producing the corresponding (Z)-isomeric amides with a high yield and selectivity. In contrast, (E)-isomeric amides exhibit lower yields and restricted applicability.

Palladium(II)-Catalyzed Decarboxylative Difunctionalization of Alkynoic Acids To Access (E)-β-Sulfonylacrylamides and DFT Study

A palladium(II)-catalyzed regio- and stereoselective difunctionalization of alkynoic acids has been achieved using sodium sulfinates and isocyanides to synthesize (E)-β-sulfonylacrylamides. The reaction proceeds via decarboxylative isocyanide addition, followed by sulfonylation. This three-component process works well with aromatic, heteroaromatic, and aliphatic alkynoic acids with good functional group tolerance and excellent regio- and stereoselectivity. DFT calculations were carried out to explain the reaction mechanism and the stereoselective formation of (E)-β-sulfonylacrylamides.

Copper-Mediated Decarboxylative Coupling of 3-Indoleacetic Acids with Pyrazolones

A copper-mediated decarboxylative coupling reaction of 3-indoleacetic acids with pyrazolones was described. This protocol realized new functionalization of pyrazolones under simple reaction conditions and exhibited high functional group compatibility and broad substrate scope. Notably, the products displayed antiproliferative activity against cancer cells.

SOMOphilic Alkynylation of Unreactive Alkenes Enabled by Iron-Catalyzed Hydrogen Atom Transfer

We report an efficient and practical iron-catalyzed hydrogen atom transfer protocol for assembling acetylenic motifs into functional alkenes. Diversities of internal alkynes could be obtained from readily available alkenes and acetylenic sulfones with excellent Markovnikov selectivity. An iron hydride hydrogen atom transfer catalytic cycle was described to clarify the mechanism of this reaction.

Copper-Mediated Decarboxylative Coupling between Arylacetic Acids and 1,3-Dicarbonyl Compounds

A copper-mediated decarboxylative coupling reaction between arylacetic acids and 1,3-dicarbonyl compounds was described. Significantly, methanocycloocta[b]indoles were also obtained by sequential intramolecular dehydrocyclization process in some cases. This protocol featured a broad substrate scope, simple operations, and good yields. Moreover, the products exhibited potent antiproliferative activity against the human cancer cell lines by a MTT assay.

Simple Synthesis of Fluorinated Ene-Ynes via In Situ Generation of Allenes

Fluorination of small molecules is a key route toward modulating reactivity and bioactivity. The 1,3 ene-yne functionality is an important synthon towards complex products, as well as a common functionality in biologically active molecules. Here, we present a new synthetic route towards fluorinated ene-ynes from simple starting materials. We employ gas chromatography-mass spectrometry analysis to probe the sequential eliminations necessary for this transformation and observe an allene intermediate. The ene-yne products are sufficiently fluorous to enable purification via fluorous extraction. This methodology will allow facile access to functional, fluorous ene-ynes.

Wonderful fusion of organofluorine chemistry and decarboxylation strategy

Decarboxylation strategy has been emerging as a powerful tool for the synthesis of fluorine-containing organic compounds that play important roles in various fields such as pharmaceuticals, agrochemicals, and materials science. Considerable progress in decarboxylation has been made over the past decade towards the construction of diverse valuable fluorinated fine chemicals for which the fluorinated part can be brought in two ways. The first way is described as the reaction of non-fluorinated carboxylic acids (and their derivatives) with fluorinating reagents, as well as fluorine-containing building blocks. The second way is dedicated to the exploration and the use of fluorine-containing carboxylic acids (and their derivatives) in decarboxylative transformations. This review aims to provide a comprehensive summary of the development and applications of decarboxylative radical, nucleophilic and cross-coupling strategies in organofluorine chemistry.

SOMOphilic alkynylation using acetylenic sulfones as functional reagents

Recent advancements in SOMOphilic alkynylation reactions by using acetylenic sulfones as functional reagents are summarized.