Coupling of arylboronic acids with benzyl halides or mesylates without adding transition metal catalysts

Transition-Metal-Free Direct α-Arylation of Weinreb-type Amides with Arylboronic Acids through Aza-oxyallyl Cation Intermediates

Here, we report an efficient transition-metal-free C(sp2)-C(sp3) Suzuki-Miyaura-type cross-coupling between α-halo Weinreb-type amides and arylboronic acids. The reaction is carried out by capturing active aza-oxyallyl cation (AOAC) with arylboronic acid to form a boron "ate" complex, followed by 1,4-migration to give α-aryl amides with good yields.

Pd(0)/Xantphos-Catalyzed Benzylic C(sp3)-O Arylation of Benzyl Heteroaryl Ethers: Reduction of Pd(II) to Pd(0) by Xantphos

Herein, we report the synthesis of 1,1-diarylmethanes via palladium-catalyzed benzylic C(sp3)-O arylation of benzyl alcohol derivatives. An efficient, straightforward approach to synthesizing Pd(0)(xantphos)2 was developed through in situ reduction of Pd(II) to Pd(0) with the bidentate tertiary phosphine xantphos, which proved to be a highly active precatalyst in the Suzuki-Miyaura cross-coupling reaction of benzyl heteroaryl ethers.

Deaminative coupling of benzylamines and arylboronic acids

A metal-free deaminative coupling of non-prefunctionalised benzylamines and arylboronic acids is reported. In this operationally simple reaction, a primary amine in benzylamine is converted into a good leaving group in situ using inexpensive and commercially available isoamyl nitrite as a nitrosating reagent. Lewis-acidic arylboronic acids are shown to replace mineral acids such as HCl or HBF₄ that are conventionally used in the preparation of aryl diazonium salts. This unlocked the formation of the corresponding diarylmethanes by forging a new C-C bond in good yields.

Broadly Applicable Ion Pair-Assisted Nucleophilic Substitution of sp3-Carbon Electrophiles with Alkynyltrifluoroborates

Alkynyltrifluoroborate nucleophiles react smoothly with a wide range of sp³-carbon electrophiles, including propargyl methanesulfonates and unactivated alkyl triflates, to give Sonogashira-type products, via a novel ion pair-assisted nucleophilic substitution mechanism. An ion pair-organic complex, investigated using computational chemistry and in situ NMR experiments, may play a crucial role in this reaction.

Boronic acid-mediated ring-opening and Ni-catalyzed arylation of 1-arylcyclopropyl tosylates

Herein, we describe a protocol for the ring-opening arylation of 1-arylcyclopropyl tosylates, in which boronic acids promote ring-opening and a Ni catalyst facilitates arylation in high regioselectivity. A number of 2-arylated allyl derivatives are synthesized, which are relevant motifs found in biologically active molecules.

Regio- and stereoselective halothiolation of alkynes using lithium halides and N-thiosuccinimides

Catalyst-free halothiolation of alkynes by using sulfenylhalide generated in situ by readily available lithium halides and N-thiosuccinimides.

Sulfur-Mediated Allylic C-H Arylation, Epoxidation, and Aziridination

Transition-metal-free, sulfur-mediated allylic C-H arylation, epoxidation, and aziridination were realized through one-pot procedures. The reaction design involved initial addition between olefins and triflic anhydride activated sulfoxides, followed by subsequent reactions of the allylic sulfur ylides generated under basic conditions with arylboronic acids, aldehydes, or aldimines, to give allylic arylation, epoxidation, or aziridination products, respectively.

Metal-free synthesis of gem-silylboronate esters and their Pd(0)-catalyzed cross-coupling with aryliodides

A transition-metal-free method for the synthesis of gem-silylboronate esters with arylboronic acids and trimethylsilyldiazomethane (TMSCHN2) has been developed. This transformation is a straightforward homologation of arylboronic acids and features wide substrate scope and good functional-group tolerance. The gem-silylboronate esters undergo efficient Suzuki-Miyaura cross-coupling with aryliodides and the silyl group of the product can be further functionalized. Tertiary carbon centers with different substituents can be constructed successfully by selective and sequential functionalization.

Applications of sulfuryl fluoride (SO2F2) in chemical transformations

A number of novel methodologies concerning the chemical, biological and medicinal applications of sulfuryl fluoride (SO₂F₂) gas have dramatically improved year by year.

Transition-Metal-Free Synthesis of Biarylmethanes from Aryl Iodides and Benzylic Ketones

An original metal-free procedure for the synthesis of biarylmethanes is disclosed herein. The reactions occur with high selectivity starting from aryl iodides and benzylic ketones in the presence of superbasic media (CsOH/DMSO). This procedure allows a straightforward access to a wide range of biarylmethane derivatives substituted with electron-withdrawing and -donating substituents.

Substrate switchable Suzuki–Miyaura coupling for benzyl ester vs. benzyl halide

Two reaction conditions were developed to accomplish the substrate switchable (benzyl esters vs. benzyl halides) Suzuki–Miyaura coupling.

Selective Synthesis of (Benzyl)biphenyls by Successive Suzuki-Miyaura Coupling of Phenylboronic Acids with 4-Bromobenzyl Acetate under Air Atmosphere

An efficient Pd-catalyzed cross-coupling reaction of phenylboronic acids and benzyl carbonates was developed, producing diarylmethanes. Benzyl acetates could also be used as coupling partners instead of benzyl carbonates, affording diarylmethanes in comparable yields. This reaction can be conducted under air atmosphere without any care for moisture and oxygen. The ester function showed an intermediate reactivity between chloro and bromo groups. This property facilitated the selective synthesis of diverse (benzyl)biphenyls by successive Suzuki-Miyaura coupling reactions using bromo- and chloro-substituted benzyl esters with two types of boronic acids.