Palladium-Catalyzed Cross-Coupling of Difluorocyclopropanes with -Diborylalkanes for the Synthesis of Boryl-Substituted Fluorinated Alkenes.

This study presents a novel method for the regioselective coupling of -difluorinated cyclopropanes with -diborylmethane, utilizing a Pd-catalyst system. This innovative approach enables the synthesis of 2-fluoroalkenyl monoboronate scaffolds with high -selectivity. The resulting products undergo further transformations, including oxidation, Suzuki cross-coupling, and trifluoroborylation, all of which are achieved with good yields.

Modular Synthesis of Fluoro-Substituted Furan Compounds via Controllable Fluorination of Biomass-Based 5-HMF and Its Derivatives.

5-Hydroxymethylfurfural (5-HMF) is regarded as one of the most promising platform feedstocks for producing valuable chemicals, fuels, and materials. In this study, we present a controllable fluorination technique for biomass-based 5-HMF and its oxygenated derivatives. This technique allows us to synthesize mono-fluoromethyl, difluoromethyl, and acylfluoro-substituted furan compounds by adjusting experimental conditions such as different fluorine sources and mole ratio.

Tunable Synthesis of Monofluoroalkenes and Gem-Difluoroalkenes via Solvent-Controlled Rhodium-Catalyzed Arylation of 1-Bromo-2,2-difluoroethylene.

Divergent synthesis of fluorine-containing scaffolds starting from a suite of raw materials is an intriguing topic. Herein, we report the solvent-controlled rhodium-catalyzed tunable arylation of 1-bromo-2,2-difluoroethylene. The selection of the reaction solvents provides switchable defluorinated or debrominated arylation from readily available feedstock resources (both arylboronic acids/esters and 1-bromo-2,2-difluoroethylene are commercially available).

Surface-Controlled CdS/Ti C MXene Schottky Junction for Highly Selective and Active Photocatalytic Dehydrogenation-Reductive Amination.

Photocatalytic valorization and selective transformation of biomass-derived platform compounds offer great opportunities for efficient utilization of renewable resources under mild conditions. Here, the novel three-dimensional hierarchical flower-like CdS/Ti C Schottky junction (MCdS) composed of surface-controlled CdS and pretreated Ti C MXene is created for photocatalytic dehydrogenation-reductive amination of biomass-derived amino acid production under ambient temperature with unprecedented activity and selectivity. Schottky junction efficiently promotes photoexcited charge migration and separation and inhibits photogenerated electron-hole recombination, which results in a super-high activity.

Photocatalytic Alkyl Radical Addition Tandem Oxidation of Alkenyl Borates.

Photocatalytic oxidation is a popular transformation way for organic synthesis and is widely applied in academia and industry. Herein, we report a blue light-induced alkylation-oxidation tandem reaction for the synthesis of diverse ketones by combining alkyl radical addition and oxidation of alkenyl borates. This reaction shows excellent functional group compatibility in acceptable yields, and diversity of radical precursors is applicable.

Synthesis of conjugated bisallenes by cooperative Cu/Pd-catalysed borylallenylation of 2-trifluoromethyl-1,3-enynes.

A cooperative Cu/Pd-catalysed borylallenylation of 2-trifluoromethyl-1,3-enynes with propargylic carbonates under mild reaction conditions was developed. This method provides facile and efficient access to conjugated bisallenes with a broad range of functional groups. Both aromatic and aliphatic 1,3-enynes can be utilized in this transformation to give the corresponding multi-substituted conjugated bisallenes.

Synthesis of -Difluorinated 1,3-Dienes via Synergistic Cu/Pd-Catalyzed Borodifluorovinylation of Alkynes.

-Difluoroalkenes (=CF), which normally act as metabolically stable bioisosteres for carbonyl groups (C═O), are widely applied in agrochemicals and pharmaceuticals and are also used as building blocks in organic synthesis. Herein, an example of Cu/Pd-catalyzed borodifluorovinylation was achieved using alkynes, difluoroethylene bromide, and Bpin as chemical feedstocks, providing the corresponding conjugated -difluoroalkene scaffold with good functional group compatibility. Moreover, an array of fluorinated synthons can be obtained through further transformations.

Three-component reaction of -difluorinated cyclopropanes with alkenes and Bpin for the synthesis of monofluoroalkenes.

Borylative difunctionalization of alkenes has emerged as a powerful approach for synthesizing highly functionalized molecules. Herein, dual Cu/Pd-catalysed borylfluoroallylation of alkenes was smoothly achieved by using gem-difluorinated cyclopropanes and B2pin2, providing the corresponding monofluoroalkene scaffolds in moderate to high yields with excellent stereoselectivity. Moreover, an array of synthetic building blocks can be obtained by downstream transformations.

Cu/Pd-Catalyzed Borylfluoroallylation of Alkynes for the Synthesis of Boryl-Substituted Monofluoroalkenes.

Monofluoroalkenes normally act as metabolically stable bioisosteres for amide groups (-NH-CO-) and have widespread applications in drug discovery. Additionally, they are widely used as building blocks in organic synthesis. In this study, the Cu/Pd-catalyzed borylfluoroallylation of alkynes was achieved, providing a modular and general tactic for the preparation of monofluorinated alkene scaffolds with high regioselectivity and stereoselectivity.

Transition-Metal-Free Valorization of Biomass-derived Levulinic Acid Derivatives: Synthesis of Curcumene and Xanthorrhizol.

Levulinic acid (LA) is acknowledged one of the most promising biomass-derived platform molecules and can be transformed into various value-added chemicals. Here, we report a new reaction process for the valorization of LA derivatives under transition-metal-free condition. The protocol combined with the conversion of the levulinate to tosylhydrazone and base promoted arylation, acylation, and etherification cross-coupling.

Three-Component Borylallenylation of Alkynes: Access to Densely Boryl-Substituted Ene-allenes.

Ene-allenes serve as versatile building blocks in organic synthesis, and the development of their efficient preparation is valuable. Herein the synthesis of boryl-substituted ene-allenes utilizing a Cu/Pd-catalyzed borylallenylation of alkynes with propargylic carbonates and bis(pinacolato)diboron is reported. Densely (tetra-, penta-, and hexa-) substituted ene-allenes were synthesized in acceptable yield with high regio- and stereoselectivity.

Access to Divergent Fluorinated Enynes and Arenes via Palladium-Catalyzed Ring-Opening Alkynylation of -Difluorinated Cyclopropanes.

Herein, we describe a palladium-catalyzed alkynylation of -difluorinated cyclopropanes via C-C bond activation/C-F bond cleavage, followed by C-C(sp) coupling. The new approach proceeds with broad substrate scope under mild reaction conditions, whereas both 1,1-disubstituted and complex-molecule-modified -difluorinated cyclopropanes react smoothly with high stereoselectivity. The developed method provides efficient and convenient ways access to diversity of important fluorinated enynes and arenes by slightly modification of the reaction conditions.

The dual-catalyzed boryldifluoroallylation of alkynes: an efficient method for the synthesis of skipped gem-difluorodienes.

The Cu/Pd-catalyzed boryldifluoroallylation of alkynes was achieved, providing the corresponding skipped gem-difluorodiene scaffolds with high regio- and stereoselectivity in moderate to excellent yields. This new approach has good functional group compatibility for both alkynes and 3,3-difluoro-substituted allylic esters. Moreover, an array of synthetic building blocks, skipped dienes, trienes, and drug mimics can be obtained via further transformations.

Regioselective β-Arylation of α-Angelica Lactone through Isomerization/Addition under Mild Conditions.

The conversion of biomass-based platform molecules into various high-value chemicals greatly promotes the utilization of renewable biomass resources. Herein, an example of Rh-catalyzed β-arylation of levulinic-acid-derived α-angelica lactone was reported, providing the γ-lactone-structure products with high regioselectivity. Both arylboronic and alkenylboronic acids could be applied in this transformation.

Palladium-Catalyzed Stereoselective Defluorination Arylation/Alkenylation/Alkylation of -Difluorinated Cyclopropanes.

A palladium-catalyzed cross-coupling of -difluorinated cyclopropanes with boronic acids, providing the corresponding arylated/alkenylated/alkylated 2-fluoroallylic scaffolds, is generated. This new approach has good functional group compatibility for both -difluorinated cyclopropanes and boronic acids; thus, an array of synthetic building blocks of monofluoroalkene scaffolds including conjugated fluorodiene and skipped fluorodiene gave good yields with high -selectivity. Moreover, proficient application was described for monofluoroalkene, whereas the corresponding alkyl fluoride was constructed through hydrogenation.

Vicinal Diboration of Alkyl Bromides via Tandem Catalysis.

Vicinal diboration of alkyl bromides via tandem catalysis is reported. The reported reaction exhibits a broad substrate scope, good functional group compatibility, and regioselectivity. Moreover, it shows good practicality due to the easy accessibility of alkyl bromides in combination with diverse transformations of diboronates.

Nickel-catalyzed allylic defluorinative alkylation of trifluoromethyl alkenes with reductive decarboxylation of redox-active esters.

Herein, we report a nickel-catalyzed allylic defluorinative alkylation of trifluoromethyl alkenes through reductive decarboxylation of redox-active esters. The present reaction enables the preparation of functionalized -difluoroalkenes with the formation of sterically hindered C(sp)-C(sp) bonds under very mild reaction conditions, while tolerating many sensitive functional groups and requiring minimal substrate protection. Therefore, this method provides an efficient and convenient approach for late-stage modification of biologically interesting molecules.

Copper-Catalyzed Reagent-Controlled Regioselective Cyanoborylation of Vinylarenes.

A copper-catalyzed borylation/benzylic cyanation of vinylarenes whose regioselectivity is seemly common but scarcely achieved is reported. This unprecedented regioselectivity is realized through a structure-distinctive cyanating reagent, dimethylmalononitrile. This reaction can be applied to both π-extended and simple vinylarenes with various diboron reagents, and it exhibits good functional group compatibility.

Rhodium(III)-Catalyzed Directed C-H Coupling with Methyl Trifluoroacrylate: Diverse Synthesis of Fluoroalkenes and Heterocycles.

An example of Rh-catalyzed C-H activation with methyl trifluoroacrylate for the synthesis of fluoroolefins and heterocycles (benzoindolizines) is reported. The types of products were determined by the directing group. The benzoindolizines and fluoroolefins were obtained by using pyridine and pyrazole as the directing group, correspondingly.

Copper-Catalyzed Alkynylboration of Alkenes with Diboron Reagents and Bromoalkynes.

An efficient method for the synthesis of homopropargylboronates by copper-catalyzed alkynylboration of alkenes with diboron reagents and bromoalkynes has been developed. The alkynylboration reaction features high selectivity and efficiency, mild reaction conditions, wide substrate scope, and functional-group compatibility, and is a highly attractive complement to existing methods for the synthesis of homopropargylboronates. Both the boryl and alkynyl groups are good potential functional groups for the subsequent manipulations that provide access to a variety of important molecule structures.

Nickel-Catalyzed Defluorinative Reductive Cross-Coupling of gem-Difluoroalkenes with Unactivated Secondary and Tertiary Alkyl Halides.

Herein, we described a nickel-catalyzed monofluoroalkenylation through defluorinative reductive cross-coupling of gem-difluoroalkenes with alkyl halides. Key to the success of this strategy is the combination of C-F cleavage with alkyl halides activation. This reaction enables the convenient synthesis of a large variety of functionalized monofluoroalkenes under mild reaction conditions with broad functional group compatibility and excellent Z-selectivity.

Copper-catalyzed/mediated borylation reactions of epoxides with diboron reagents: access to β-hydroxyl boronic esters.

We report the first copper-catalyzed/mediated borylative ring opening reaction of epoxides. This process represents a direct borylative C(sp)-O bond cleavage of terminal epoxide substrates with commercially available diboron reagents. A wide range of epoxides with different functional groups are involved, and were subsequently converted to the corresponding β-hydroxyl boronic esters smoothly.

1,1-Disubstituted olefin synthesis via Ni-catalyzed Markovnikov hydroalkylation of alkynes with alkyl halides.

A Ni-catalyzed Markovnikov hydroalkylation of alkynes with alkyl halides is described. The reaction proceeds smoothly without the use of sensitive organometallic reagents and shows good functional-group compatibility, enabling the efficient synthesis of a variety of 1,1-disubstituted olefins. It also provides a straightforward approach for the modification of complex organic molecules.

Copper-catalyzed cross-coupling reactions of epoxides with gem-diborylmethane: access to γ-hydroxyl boronic esters.

Herein, we describe a novel copper-catalyzed epoxide opening reaction with gem-diborylmethane. Aliphatic, aromatic epoxides as well as aziridines are converted to the corresponding γ-pinacolboronate alcohols or amines in moderate to excellent yields. This new reaction provides beneficial applications for classic epoxide substrates as well as interesting gem-diborylalkane reagents.

Ligand-Controlled Regiodivergent Copper-Catalyzed Alkylboration of Alkenes.

A novel copper-catalyzed regiodivergent alkylboration of alkenes with bis(pinacolato)diboron and alkyl halides has been developed. The regioselectivity of the alkylboration was controlled by subtle differences in the ligand structure. The reaction thus enables the practical, regiodivergent synthesis of two different alkyl boronic esters with complex structures from a single alkene.