Acyl fluorides as direct precursors to fluoride ketyl radicals: reductive deuteration using SmI2 and D2O

Samarium diiodide/samarium-mediated direct deoxygenative hydroborylation of ketones with hydroborane esters

A direct deoxygenative hydroborylation of ketones with hydroborane ester promoted by a combination of samarium diiodide, samarium and nickel has been developed. In this method, secondary alkyl borate esters are synthesized from unactivated ketones with hydroborane esters in one step. A broad substrate scope and excellent selectivity toward CO cleavage has been demonstrated. This approach represents a general method for the construction of versatile secondary alkyl borate esters from unactivated ketones.

Photocatalyzed Aryl C-H Fluorocarbonylation with CF2Br2

The use of abundant and inexpensive fluorine feedstocks to synthesize fluorinated compounds is a promising strategy that has not been extensively investigated. Dibromodifluoromethane (CF2Br2) is an inexpensive fluorine source that has rarely been used for C-H fluoroalkylation. This study reveals an iridium-catalyzed, tunable strategy for synthesizing acyl fluorides and difluorobromomethylated products using CF2Br2. To achieve the desired products, this process only requires the change of solvent (from DMSO to 1,4-dioxane) under blue LED illumination. A variety of arenes and heteroarenes with electron-donating substituents were successfully used, yielding the corresponding products in moderate to good yields. Mechanistic experiments revealed that DMSO served a dual role, functioning as both solvent and nucleophilic reagent in C-H fluorocarbonylation.

Highly effective and selective FeBr3-promoted deuterium bromination/cyclization of 1,n-enynes

A highly effective and selective FeBr3-promoted deuterium bromination/cyclization of 1,n-enynes is reported. On the one hand, the Lewis acid FeBr3 as a catalyst promotes cyclization of 1,n-enynes to afford deuterium heterocyclic frameworks with high efficiency. On the other hand, FeBr3 serves as the bromine source (with D2O as the deuterium source) to promote the formation of the desired deuterated pyrrole derivatives containing alkenyl bromide groups. This protocol provides an effective pathway to afford deuterated alkenyl brominative compounds as (Z)-isomers with high yields and selectivity, offering a new method for introducing 2H into organic compounds.

Single Electron Transfer Reductive Deuteration of Acyl Chlorides for the Synthesis of Deuterated Alcohols with a High Deuterium Atom Economy

We present a highly deuterium atom economical approach for the synthesis of deuterated alcohols via the single electron transfer (SET) reductive deuteration of acyl chlorides. Cost-effective sodium dispersion and EtOD-d1 were used as the single electron donor and deuterium donor, respectively. Our approach achieved up to 49% deuterium atom economy, which represents the highest deuterium atom economy yet achieved in SET reductive deuteration reactions. With all 20 tested substrates, excellent regioselectivity and >92% deuterium incorporations were obtained. Furthermore, we demonstrated the potential of this methodology by synthesizing four deuterated analogues of pesticides.

Reductive Deuteration of Acyl Chlorides for the Synthesis of α,α-Dideuterio Alcohols Using SmI2 and D2O

The synthesis of α,α-dideuterio alcohols has been achieved via single electron transfer reductive deuteration of acyl chlorides using SmI₂ and D₂O. This method is distinguished by its remarkable functional group tolerance and exquisite deuterium incorporation, which has also been applied to the synthesis of valuable deuterated agrochemicals and their building blocks.

One-Pot Sequential Hydrogen Isotope Exchange/Reductive Deuteration for the Preparation of α,β-Deuterated Alcohols using Deuterium Oxide

An efficient one-pot sequential hydrogen isotope exchange (HIE)/reductive deuteration approach was developed for the preparation of α,β-deuterated alcohols using ketones as the precursors. The HIE step can also be used for the synthesis of α-deuterated ketones. This method has been applied in the synthesis of four deuterated drug and MS internal standards.

Selective Reduction of Quinolinones Promoted by a SmI2/H2O/MeOH System

The selective reduction of quinolin-2(1H)-ones promoted by a SmI₂/H₂O/MeOH system is reported for the first time. The reaction is effectively carried out to afford 3,4-dihydroquinoline-2(1H)-ones under mild conditions in a one-pot fashion with good to excellent yields.

Recent Advances in C–F Bond Activation of Acyl Fluorides Directed toward Catalytic Transformation by Transition Metals, N-Heterocyclic Carbenes, or Phosphines

Numerous studies on the activation of carbon–fluorine bonds have been reported in recent years. For example, acyl fluorides have been utilized as versatile reagents for acylation, arylation, and even fluorination. In this review, we focus on acyl fluorides as compounds with carbon–fluorine bonds, and highlight recent advances in strategies for the activation of their C–F bonds via transition-metal catalysis, N-heterocyclic carbene (NHCs) catalysis, organophosphine catalysis, and classical nucleophilic substitution reactions.

1 Introduction

2 Transition-Metal-Mediated C–F Bond Activation

2.1 Acylation (Carbonyl-Retentive) Coupling Reactions

2.2 Decarbonylative Reactions

2.3 C–F Bond Activation by Other Transition Metals

3 C–F Bond Activation by N-Heterocyclic Carbenes (NHCs)

3.1 NHC-Catalyzed Cycloaddition of Acyl Fluorides

3.2 NHC-Catalyzed Radical Functionalization of Acyl Fluorides

3.3 NHC-Catalyzed Nucleophilic Fluorination of (Hetero)aromatics

4 C–F Bond Activation by Phosphines

4.1 Phosphine-Catalyzed Direct Activation of the C–F Bond of Acyl Fluorides

4.2 Phosphine-Catalyzed Indirect Activation of the C–F Bond of Acyl Fluorides

5 C–F Bond Activation by Classical Nucleophilic Substitution

6 Miscellaneous Examples

7 Summary and Perspective

Programmable iodization/deuterolysis sequences of phosphonium ylides to access deuterated benzyl iodides and aromatic aldehydes

Herein, a tunable iodization/deuterolysis protocol for phosphonium ylides by employing D₂O as the deuterium source was designed. Notably, this process could be manipulated by tuning the base, thus leading to two valuable deuterated building blocks - benzyl iodides and aromatic aldehydes with broad substrate scope, good functional group compatibility and excellent deuteration degree. Concise syntheses of a series of deuterated drug analogues have been achieved based on the developed deuteration reaction platform.

Current Electrochemical Approaches to Selective Deuteration

The selective deuteration of organic molecules through electrochemistry is proving to be an effective alternative to conventional 2H labelling strategies, which traditionally require high temperatures, high pressures of deuterium gas...