Issues related to the use of sulfur based fluorination and fluoroalkylation reagents for the synthesis of organic chemicals are discussed. Topics discussed include using sulfoximines as ...perfluoroalkylation reagents and sulfonium salts as perfluoroalkylation reagents.
Fluorinated sulfinate salts RfSO2Na (Rf = CF2H, CF2Ph, and CH2F) have been prepared via NaBH4-mediated reduction of the corresponding benzodthiazol-2-yl sulfones, and their synthetic application as ...di- and monofluoroalkyl radical precursors is demonstrated in the silver-catalyzed cascade fluoroalkylation/aryl migration/SO2 extrusion of conjugated N-arylsulfonylated amides.
Owing to the excellent performance of fluorinated compounds in the areas of pharmaceuticals, agrochemicals, and materials chemistry, organic chemists have made great efforts towards the selective ...incorporation of fluorine or fluorinated moieties into organic molecules through nucleophilic, electrophilic, radical, and metal‐catalyzed pathways. Impressive progress in fluorination and perfluoroalkylation (especially trifluoromethylation) reactions has been made over the past few decades. However, methods for incorporating lightly fluorinated groups (such as −CF2H) are still underdeveloped, in spite of their important applications in pharmaceuticals and agrochemicals. This Focus Review summarizes recent developments in metal‐catalyzed direct difluoromethylation reactions.
Fluoro and fauna: The incorporation of CF2H groups into organic compounds has attracted much recent attention, owing to the broad applications of CF2H‐containing compounds in pharmaceuticals and agrochemicals. Metal‐catalyzed direct difluoromethylation represents one of the most powerful tools for the synthesis of difluoromethylated compounds. This Focus Review describes the recent developments and remaining challenges in this field.
Radical fluoroalkylation of alkenes has been developed by electrochemical reduction of fluoroalkyl sulfones. A series of electron-deficient alkenes readily undergo hydrofluoroalkylation in good to ...excellent yields. This chemistry represents the first example of electrochemical generation of fluoroalkyl radicals from sulfones, which are used for practical radical fluoroalkylation of organic compounds.
Radical fluoroalkylation of alkenes has been developed by electrochemical reduction of fluoroalkyl sulfones.
An unprecedented hypervalent iodine(III) catalyzed Balz–Schiemann reaction is described. In the presence of a hypervalent iodine compound, the fluorination reaction proceeds under mild conditions ...(25–60 °C), and features a wide substrate scope and good functional‐group compatibility.
Iodine helps fluorine: A hypervalent iodine(III)‐catalyzed Balz–Schiemann fluorination reaction of arenediazonium salts features a wide substrate scope and good functional group compatibility. The addition of a hypervalent iodine compound enables the fluorination to proceed under mild conditions (25–60 °C).
A new strategy for the synthesis of aryl trifluoromethyl ethers (ArOCF3) by combining O-carboxydifluoromethylation of phenols and subsequent decarboxylative fluorination is reported. This protocol ...allows easy construction of functionalized trifluoromethoxybenzenes and trifluoromethylthiolated arenes (ArSCF3) in moderate to good yields. Moreover, it utilizes accessible and inexpensive reagents sodium bromodifluoroacetate and SelectFluor II and, thus, is practical for O-trifluoromethylation of phenols. The potential application of this method is demonstrated with the preparation of a plant-growth regulator, Flurprimidol.
Fluorinated ketones are intriguing compounds in synthetic chemistry and life science‐related fields. The development of efficient methodologies to obtain these compounds is of significant importance ...and has therefore attracted considerable attention. This Minireview highlights recent progress made in the synthesis of fluorine‐containing ketones, with an emphasis on those methods in which the construction of carbonyl groups is synergetic with distal (β‐, γ‐, δ‐, etc.) incorporation of fluorine atoms or fluorinated groups.
One step to fluorinated ketones: The development of efficient methodologies to obtain distally fluorinated ketones is a rapidly growing area of synthetic chemistry and life‐science‐related fields. In this Minireview, some recent important advances in this area are presented and their reaction mechanisms are also discussed.
Abstract
Direct deoxyazidation of alcohols with NaN
3
is a straightforward method for the synthesis of widely used alkyl azides in organic chemistry. However, known methods have some limitations such ...as high reaction temperatures and narrow substrate scope. Herein, a general and practical method for the preparation of alkyl azides from alcohols using NaN
3
has been developed.
N
-tosyl-4-chlorobenzenesulfonimidoyl fluoride (SulfoxFluor) plays an important role in this deoxyazidation process, which converts a broad range of alcohols into alkyl azides at room temperature. The power of this deoxyazidation protocol has been demonstrated by successful late-stage deoxyazidation of natural products and pharmaceutically relevant molecules.
A general method for the efficient difluoromethylation of alcohols using commercially available TMSCF2Br (TMS=trimethylsilyl) as a unique and practical difluorocarbene source is developed. This ...method allows primary, secondary, and even tertiary alkyl difluoromethyl ethers to be synthesized under weakly basic or acidic conditions. The reaction mainly proceeds through the direct interaction between a neutral alcohol and difluorocarbene, which is different from the difluoromethylation of phenols. Moreover, alcohols containing other moieties that are also reactive toward difluorocarbene can be transformed divergently by using TMSCF2Br. This research not only solves the synthetic problem of difluorocarbene‐mediated difluoromethylation of alcohols, it also provides new insights into the different reaction mechanisms of alcohol difluoromethylation and phenol difluoromethylation with difluorocarbene species.
A general method for difluoromethylation of alcohols with difluorocarbene under weakly basic or acidic aqueous conditions by using TMSCF2Br as a unique and practical difluorocarbene reagent is developed. This method is efficient for the selective synthesis of alkyl difluoromethyl ethers from functionalized alcohols, and a mechanism different from difluoromethylation of phenols is disclosed.
Abstract
The new millennium has witnessed the rapid development of synthetic organofluorine chemistry all over the world, and chemists in China have made significant contributions in this field. This ...review aims to provide a brief introduction to China's primary innovations from 2000 to early 2017, covering fluorination, fluoroalkylation, fluoromethylthiolation, fluoroolefination and polyfluoroarylation, as well as synthesis with fluorinated building blocks. Recent advances in the chemistry of difluorocarbene and the chemistry of carbon–fluorine bond activation are also discussed. As a conclusion, the review ends with some personal perspectives on the future development of China's synthetic organofluorine chemistry.
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