Transition-Metal-Free Decarboxylative Coupling Reactions for the Synthesis of Propargyl Alcohols

Synthesis of primary propargylic alcohols from terminal alkynes using rongalite as the C1 unit

Here, an efficient leaving group-activated methylene alcohol strategy for the preparation of primary propargyl alcohols from terminal alkynes by employing the bulk industrial product rongalite as the C1 unit has been described. The reaction avoids the low-temperature reaction conditions and inconvenient lithium reagents required for the classical method of preparing primary propargylic alcohols. Preliminary mechanistic studies showed that the reaction may not proceed via formaldehyde intermediates, but through the direct nucleophilic attack of the terminal alkyne on the carbon atom of rongalite by activation through SO₂^- as a leaving group.

Biaryl Formation via Base-Promoted Direct Coupling Reactions of Arenes with Aryl Halides

In the absence of ligand, Cs2CO3-promoted cross-coupling reaction of arenes with cyano-/nitro-substituted aryl halides in DMSO affording biaryls is reported. The cyano/nitro group in biaryls is useful and convenient for further transformation. The formation of dibenzofurans resulting from the reactions between arenes and 1-bromo-2-iodobenzene is also reported. On the basis of control experiments and theoretical studies, a radical mechanism is proposed for the formation of biaryls.

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.