Synthesis of Symmetrical Biaryls via Rhodium Catalyzed Dimerization of Arylmercurials and Mechanism of the Dimerization

A series of symmetrical biaryls was synthesized from arylmercuric chlorides and biarylmercurials in the presence of [ClRh(CO) 2] 2 in hexamethylphosphoramide(HMPA). The mechanism of the [ClRh(CO) 2] 2 catalyzed dimerization of biarylmercurials was studied, and shown to be mainly intermolecular reaction.

An Efficient Palladium-catalyzed Coupling Reaction for the Preparation of Biaryls and Polyaryls

In the case of Pd(PPh3)4 as catalyst and toluene as reaction solvent, the desired biaryls and polyaryls were synthesized in excellent yield and on a large scale.

A facile approach to asymmetrical biaryls via coupling reaction of aryl halides with sodium tetraphenylborate catalyzed by MCM-41-supported sulfur palladium(0) complex

Various functionalized asymmetrical biaryls can be synthesized in high to excellent yields via coupling reaction of aryl iodides or bromides with NaBPh4 catalyzed by MCM-41-supported sulfur palladium（0） complex. This palladium complex can be easily recovered and reused many times without loss of activity.

Synthesis of 3-Biaryl-1-ferrocenyl-2-propene-1-ones

The novel structures of organometallic compounds 3-biaryl-1-ferrocenyl-2-propene- 1-ones 5 were synthesized for nonlinear optical chromophores by Suzuki cross-coupling reaction. Their structures were determined with elemental analyses, 1H NMR spectra and 13C NMR spectra.

Palladium Catalyzed Synthesis of Fluorine-containing 3-Biaryl-1-ferrocenyl-2-propene-1-one

The novel organometallic compounds, 3-[4'(or 2')-(4''-fluorophenyl)] phenyl-1-ferroc- enyl-2-propen-1-ones 5 were synthesized for nonlinear optical chromophores by Pd (0) catalyzed Suzuki cross-coupling reaction. Their structures were established with elemental analysis, MS, IR and H NMR spectroscopies. 1

Synthesis of biaryls using palladium nanoparticles immobilized on peptide nanofibers as catalyst and hydroxybenzotriazole as novel phenylating reagent

Peptide nanofibers decorated with palladium nanoparticles catalyzed direct coupling of aryl halides with hydroxybenzotriazole to afford the corresponding biaryls in good to excellent yields.The coupling reactions proceeded under simple,green,and mild conditions.The peptide nanofibers were used as recyclable supports in the coupling reactions.This approach is the first to use hydroxybenzotriazole as a phenylating agent.

Photocatalytic Site-Selective Cascade Radical Addition of Biaryl Ynones for the Construction of Spiro-and Fused Carbon Rings

Functionalized free radical addition/cyclization reactions represent an efficient way for introducing new functionality or coupling fragments to molecules.Ynones are good regional selectivity radical acceptors in organic synthesis,and many of bio-relevant cyclic compounds could be easily obtained by direct radical cyclization reaction.Here,we report a photocatalytic cascade radical addition of biaryl ynones,for the divergent synthesis of privileged carbon cycles.Additionally,further transformation of the multi-functional group product into a variety of other derivatives demonstrates the synthetic value of this developed method.

An unprecedented synthesis of axially chiral biaryls by rearrangement and aromatization of carbocations with central-to-axial conversion of chirality

The central-to-axial chirality conversion represents a fascinating class of chemical processes consisting of the destruction of stereogenic centers and the simultaneous installation of axial chiral elements,which provides efficient methods for the preparation of axially chiral compounds.However,developing catalytic asymmetric approaches for constructing these central chirality precursors and the efficient central-to-axial chirality conversion remains a challenge due to the requirement of aromatization or elimination process.In this work,we have developed an unprecedented enantioselective intramolecular FriedelCrafts alkylation with unactivated-ketone carbonyls from which a chiral tertiary alcohol was generated with high efficiency and excellent enantioselectivity.In addition,the central-to-axial chirality conversion strategy has been successfully applied to the synthesis of enantioenriched biaryls via a less-explored carbocation-initiated rearrangement and aromatization under the promotion of Lewis acid.This methodology provided a straightforward and sustainable access to a broad range of biaryl-2-carboxylic acid and in excellent yields(up to 92%)and excellent central-to-axial chirality conversion(up to 99%conversion percentage).This work could be a great model for developing new methods for synthesizing axially chiral biaryls and a general protocol for the rearrangement and aromatization of carbocations for further functionalization.

Carbene-Catalyzed Asymmetric Ring-Opening Reaction of Biaryl Lactams to Access Axially Chiral Biaryls

Axially chiral biaryls represent the most important class of atropisomers,and they widely exist in natural products and biologically active molecules.They also constitute a unique scaffold for chiral ligands and catalysts in organic synthesis.The development of synthetic methods to obtain such chiral compounds has received widespread attention,among which catalytically atroposelective ring-opening of configurationally labile compounds represents one of the most attractive strategies.Various substrates with strained cyclic structures,such as the renowned Bringmann's lactones,can undergo asymmetric transformation into stable atropisomers.Known advancement primarily relies on metal catalyst combined with well-designed chiral ligands,the approaches utilizing organocatalysis as a critical resolution strategy are notably scarce.In this study,we disclosed a N-heterocyclic carbene(NHC)-catalyzed asymmetric ring-opening reaction of biaryl lactams via direct atroposelective nucleophilic activation.The optimized bulky carbene catalyst ensures that the reaction can proceed under mild conditions,affording the desired product with good to excellent yields and atroposelectivity.

Catalytic Atroposelective Catellani Reaction Enables Construction of Axially Chiral Biaryl Monophosphine Oxides

An unprecedented atroposelective Catellani reaction between phosphine oxide-containing aryl bromides,aryliodides,and nucleophiles for the construction of phosphine-containing biaryl atropisomers was established using an enantiopure norbornene derivative as the chiral mediator.A broad range of atropisomeric biaryl-based monophosphine oxides were obtained in good efficiency with excellent enantioselectivity.

Efficient P-Chiral Biaryl Bisphosphorus Ligands for Palladium-Catalyzed Asymmetric Hydrogenation

A series of structurally novel P-chiral biaryl bisphosphorus ligands L1-L5 （BABIBOPs） are developed, providing high efficiency for the first time in palladium-catalyzed asymmetric hydrogenation of β-aryl and β-alkyl substituted β-keto esters. With the Pd-1.3 （iPr-BABIBOP） catalyst, a series of chiral β-hydroxyl carboxylic esters are formed in excellent enantioselectivities （up to 〉 99% ee） and yields at catalyst loading as low as 0.01 mol%.

Ni-Catalyzed Cross Coupling ofAryl Grignard Reagents with Aryl Halides in a Nonpolar Solvent and an Efficient Synthesis of Biaryls Under Neat Conditions

This study details Ni-catalyzed cross coupling of aryl Grignard reagents with aryl halides in toluene, a nonpolar solvent with a high boiling point. The reaction was applied for the synthesis of various biaryls in good yields without the introduction of a large steric ligand. The Kumada-Tamao-Corriu（KTC） reaction in toluene was then successfully modified to proceed under neat conditions for the efficient syntheses of symmetrical biaryls, particularly in large-scale preparations. Unactivated aryl chlorides show higher reactivity than aryl bromides, particularly under neat conditions. Mechanistic investigations suggest a radical procedure for the catalytic cycle, and the origin of the radical intermediates being aryl halides.

Mild and highly regioselective synthesis of biaryl acids via Rh （I）-catalyzed cross-dehydrogenative coupling of benzoic acids using sodium chlorite as oxidant

A mild and efficient synthesis for the biaryl acids via rhodium-catalyzed cross-dehydrogenative coupling reaction has been developed. This novel protocol with sodium chlorite as an oxidant featured many advantages such as mild reaction conditions, high regioselectivity, tolerance of various functional groups, and good to excellent yields.

Palladium-catalyzed ortho-C–H silylation of biaryl aldehydes using a transient directing group

A strategy for Pd-catalyzed ortho-C–H silylation of biaryl aldehydes enabled by a transient auxiliary is presented. This protocol provides a broad range of ortho-silylated biaryl aldehydes in good yields. The silyl moiety can be further functionalized under mild conditions, rendering the silylated products useful building blocks. Notably, this protocol also offers an opportunity to establish a platform for expeditious synthesis of structurally diverse axially chiral biaryl aldehydes via sequential atroposelective interannular C–H functionalization/intraanular C–H silylation.

Theoretical insights into the [4+2]/retro [4+2] cycloaddition approach to the synthesis of biaryls and polycyclic aromatics

A domino [4+2]/retro [4+2] cycloaddition process of cyclohexadienes with arylethynes or benzyne providing access to biaryls and polycyclic aromatics has been studied theoretically using density functional theory calculations. It has been found that the initial Diels-Alder (D-A) reaction acts as the rate-determining step and the consequent [4+2] cycloreversion reaction is feasible under the conditions used. Furthermore, the D-A reaction affects the regioselectivity, the origin of which is essentially derived from the good match of orbital coefficients between dienes and dienophiles as shown by using frontier molecular orbital (FMO) theory. Further investigation of the reactivity reveals that the reactions are predicted to fail to occur if an electron-donor group in the diene or an electron-acceptor group in the dienophile is lacking, as a consequence of the increased FMO energy gap. By further exploring the scope of substrates computationally, benzyne as an active dienophile was predicted to react with a variety of dienes in a cascade reaction under mild conditions with a low energy barrier, with the rate-determining step being the retro [4+2] cycloaddition.

Optimized Palladium（0）-catalyzed Suzuki Cross-coupling Reaction of Polystyrene-supported Selenenyl Flavanones： A Convenient Preparation of Biaryl-chromen-4-one

Application of the Suzuki cross-coupling reaction for efficient synthesis of diverse substituted biaryl-chromen- 4-ones using an optimized palladium（0） catalyst system is reported. The coupling of arylboronic acids with the resin-bound bromoflavanones which were prepared by organoselenium-induced regioselective intramolecular cy- clization of bromo-2-hydroxylchalcones proceeded smoothly. Biaryl-chromen-4-ones were synthesized by subse- quent selenoxide syn-elimination in good total yields.

Ion-Pairing Chirality Transfer in Atropisomeric Biaryl-Centered Gold Clusters

The stereocontrol of chiral metal clusters and nanoclusters has become a focus of interest in metal cluster chemistry due to their promising applications in asymmetric catalysis.Despite being a general chirality transfer strategy,the ion-pairing process is still ambiguous in the course of bestowing chirality to metal clusters.Here we construct a biaryl-centered axially chiral gold-cluster system to study an outside-in ion-pairing chirality transfer process.Four hexanuclear gold(I)clusters,centered by two types of biaryl ligands[(2-indolyl)aniline(L^(1))and biindole(L^(2))],were synthesized via in situ cyclization reactions.In the crystalline state,the biaryl centers showed axial chirality in which the gold atoms were in an asymmetric arrangement.In solution,the chiral phosphates induced an outside-in chirality transfer by significant interactions with the periphery of the biaryl-centered gold clusters.Finally,the chiral resolution of hexa-aurated biindoliums was accomplished via an efficient outside-in chirality transfer process relying on strong aurophilic interaction and extra peripheral coordination.This study not only deepens the understanding of the outside-in ion-pairing chirality transfer process but also provides a new approach for fabricating desired chiral metal clusters by a combination of organometallic transformation and chirality transfer.

Merging C–H and C–C Activation in Pd(Ⅱ)-Catalyzed Enantioselective Synthesis of Axially Chiral Biaryls

The merging of C-H and C-C bond cleavage into one single chemical process remains a daunting challenge,especially in an asymmetric manner.Herein,a Pd(Ⅱ)-catalyzed enantioselective tandem C-H/C-C activation for the synthesis of axially chiral biaryls is described.Two types of simple cyclopropanes,such as vinylcyclopropanes and cyclopropanols,were used as efficient and readily available coupling partners.

One-pot synthesis of salicylaldehyde containing biaryl frameworks via an aminocatalytic Diels-Alder-retro-Diels-Alder cascade reaction of ynals with 2-pyrones

Salicylaldehyde containing biaryls are efficiently synthesized via an unprecedented amine promoted Diels-Alderretro-Diels-Alder cascade reaction of ynals with 2-pyrones in good yields.The reaction is instrumentally metalfree,operationally simple and mild,and tolerates a diverse array of functional groups.

N-杂环卡宾Pd络合物催化的Suzuki-Miyaura反应

合成了N-杂环卡宾环金属Pd络合物,评价了它们在Suzuki-Miyaura偶联反应中的催化性能,发现其可催化氯代芳烃,包括未活化的4-氯甲苯,与苯硼酸反应高产率地生成相应的联芳烃产物.