Publications by authors named "Yun-He Xu"

Reaction optimization plays an essential role in chemical research and industrial production. To explore a large reaction system, a practical issue is how to reduce the heavy experimental load for finding the high-yield conditions. In this paper, we present an efficient machine learning tool called "RS-Coreset", where the key idea is to take advantage of deep representation learning techniques to guide an interactive procedure for representing the full reaction space.

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This study presents a copper-catalyzed, substrate-controlled regio- and enantioselective intermolecular hydrosilylation method capable of accommodating a broad scope of alkenes and prochiral silanes. The approach offers an efficient and versatile pathway to generate enantioenriched linear and branched alkyl-substituted Si-stereogenic silanes. Key features of this reaction include mild reaction conditions, simple catalytic systems, compatibility with diverse substrates, high yields and enantioselectivities.

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A copper-catalyzed efficient regioselective silylation reaction of chloro-substituted allenyl-Bdan was developed. Under mild reaction conditions, allenyl and propargyl silane compounds can be selectively obtained in moderate to high yields by adjusting the bases and solvents used in the reactions. This study offers direct and efficient methods for synthesizing multifunctionalized allenyl and propargyl silane compounds from the same initial material of chloro-substituted allenyl-Bdan.

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Herein, we present catalyst-regulated switchable site-selective hydrosilylation of enynes, which are suitable for a wide range of alkyl and aryl substituted polar enynes and exhibit excellent functional group compatibility. Under the optimized conditions, silyl groups can be precisely installed at various positions of 1,3-dienes. While α- and γ-silylation products were obtained under platinum-catalytic systems, β-silylation products were delivered with [Cp*RuCl] as catalyst.

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We develop a copper-catalyzed disilylation of polysubstituted pent-1-en-4-yn-3-yl acetate derivatives, which in one pot furnishes the bis(silyl)-substituted vinylallenes in moderate yields under mild reaction conditions. The reaction shows broad substrate scope and single stereoselectivity. Besides, we develop a method to decrease the electrocyclization temperature of vinylallenes for the synthesis of methylenecyclobutenes by installing bis(silyl) substituents.

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We report a copper-catalyzed ligand-controlled selective 1,2- and 1,4-hydrosilylation of 1,3-enynes, which furnishes enantiomerically enriched propargyl- and 1,2-allenylsilane products in high yields with excellent enantioselectivities (up to 99% ee). This reaction proceeds under mild conditions, shows broad substrate scope for both 1,3-enynes and trihydrosilanes, and displays excellent regioselectivities. Mechanistic studies based on deuterium-labeling reactions and density functional theory (DFT) calculations suggest that allenylcopper is the dominant reactive intermediate under both 1,2- and 1,4-hydrosilylation conditions, and it undergoes metathesis with silanes via selective four-membered or six-membered transition state, depending on the nature of the ligand.

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In this protocol, a copper-catalyzed desymmetric protosilylation of prochiral diynes was developed. The corresponding products were obtained in moderate to high yields and enantiomeric ratios. This approach provides a simple method for synthesizing functionalized chiral tertiary alcohols in the presence of a chiral pyridine-bisimidazoline (Pybim) ligand.

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The three-component coupling method for regio- and stereoselective difunctionalization of allenes with allenyl ethers, bis(pinacolato)diboron, and -dichlorocyclobutenones as electrophiles was reported, yielding a variety of highly functionalized cyclobutenone products tethering with an alkenylborate fragment. The polysubstituted cyclobutenone products also underwent diverse transformations.

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We report copper-catalyzed borylation and silylation of dichlorocyclobutenones, which furnish the boron-substituted and siliconsubstituted polyfunctionalized cyclobutenones in high yields. The reactions proceed under mild reaction conditions, show broad substrate scope, and display high chemoselectivity. In addition, a series of transformations of the corresponding products has been realized.

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A novel strategy of copper-catalyzed regio- and enantioselective hydrosilylation of 4-substituted vinylidenecyclohexanes with silanes was developed. In this protocol, various allenes and silanes were used to afford the corresponding (cyclohexylidene)ethyl silanes in moderate to high yields with good enantioselectivities.

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A copper-catalyzed regioselective Markovnikov 3,4-hydrosilylation of 2-substituted 1,3-dienes has been accomplished. A wide range of 2-substituted 1,3-dienes and trihydrosilanes are compatible under the optimal conditions. The bisphosphine ligand with a rigid backbone provides the Markovnikov 3,4-hydrosilylation product in better yield and selectivity.

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A copper-catalyzed 1,4-protosilylation of α-alkynyl-enones to form the functionalized chiral homoallenylsilanes was developed. In the presence of a chiral monopyridine oxazoline ligand, a variety of trisubstituted allene derivatives bearing a contiguous stereogenic center and axis were prepared in good yields with excellent enantioselectivities and diastereoselectivities.

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A copper-catalyzed borylation of propargyl dichlorides was developed under mild reaction conditions. The corresponding chloro-substituted allenyl-Bdan products were obtained in good yields. The utilities of allenyl-Bdan products were examined by their diverse derivatizations.

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A copper-catalyzed regiodivergent hydrosilylation of a wide range of simple allenes is reported. Linear and branched allylsilanes were formed by judicious choice of solvents. Furthermore, branched allylsilanes were obtained with high enantioselectivity (up to 97% enantiomeric excess) with the aid of a C2-symmetric bisphosphine ligand in the unprecedented asymmetric allene hydrosilylation.

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In this protocol, an efficient palladium-catalyzed asymmetric synthesis of axially chiral conjugated dienes via alkenyl C-H olefination is reported. The corresponding atropisomeric styrenes containing a conjugated diene scaffold were obtained in good yields with good enantioselectivities. This synthetic strategy features an easy operation, mild reaction conditions, a wide functionality tolerance, and high efficiency.

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A convenient method for the dienylation of -benzoylhydrazones in water has been developed. This protocol expanded the synthetic application of functionalized homoallenylboronates to provide the useful 2-aminomethyl-1,3-diene derivatives with high efficiency (up to 99% yield) and stereoselectivity without using any catalyst, additive or inert atmosphere. Furthermore, the transformation of a 2-aminomethyl-1,3-diene derivative to synthesize a functionalized pyrrolidine derivative was also explored.

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Unprecedented copper-catalyzed regiodivergent hydrosilylation reactions of substituted 1,3-dienes with hydrosilanes have been developed. The 1,2- and 1,4-hydrosilylations of 1-(hetero)aryl-substituted 1,3-dienes were highly selectively controlled via variation of the catalytic systems. Meanwhile, the 1,4-hydrosilylation reaction of 2-aryl-substituted 1,3-dienes with diphenylsilane was also successfully realized for the first time.

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In this protocol, copper-catalyzed diverse silylative carbocyclization reactions of 2,2'-diethynylbiaryl derivatives with silaboronate were reported. Three new and novel types of domino reactions for the copper-catalyzed transformation of silaboronate were discovered. The corresponding cyclobuta[]phenanthrene, bis((silyl)methyl)phenanthrene, and silyl-substituted exocyclic diene products were chemoselectively formed with high efficiency.

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In this protocol, the chemoselective defluoromethoxylation reactions of 2-trifluoromethyl-1,3-enynes were developed. The enynic and allenic orthoesters were selectively produced in good to excellent yields via multiple substitution processes under mild reaction conditions, respectively. The enynic orthoester products were proved capable of acting as efficient "platform molecules" to access various functionalized allenyl compounds.

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A copper-catalyzed -Markovnikov hydrosilylation of alkynes with PhSiH was reported. This reaction represents a notable and efficient example on copper-catalyzed hydrosilylatioin of alkynes, which shows excellent recognition between the terminal and internal triple bonds. Various (hetero)aromatic and aliphatic substituted terminal alkynes underwent this reaction to afford the ()-vinylsilanes in high yields and with excellent regioselectivity.

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Osteogenesis induced by mechanical stretch is the main factor affecting the orthodontic treatment. Due to the masticatory force transmitted by tooth, human periodontal ligament fibroblasts (hPDLFs) could enhance osteogenic differentiation, and remolding of periodontal. Therefore, in-depth study of hPDLFs osteogenic differentiation and its regulatory mechanism is helpful in the understanding of periodontal remolding promoted by orthodontic force.

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The Cu-catalyzed 1,4-protosilylation and protoborylation of trifluoromethyl-substituted conjugated enynes were developed to access functionalized homoallenylsilanes and homoallenylboronates. This protocol also provides a general method to synthesize optically active homoallenylsilanes and homoallenylboronates in moderate to excellent yields with high enantiomeric excess by using new designed chiral bisoxazoline ligands. Simultaneously, the transformations of homoallenylsilanes and homoallenylboronates were also explored to synthesize useful building blocks.

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A novel method of metal-free dehydrogenative silylation of enamides has been developed. The desired functionalized vinylsilane products were obtained in moderate to good yield and with high stereoselectivities. This protocol displays good tolerance of various functionalities.

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A copper-catalyzed silylation of propargyl dichlorides was developed to access chloro-substituted allenylsilanes under mild reaction conditions. Moreover, enantioenriched chloro-substituted allenylsilanes can be synthesized in moderate to high yields and good enantioselectivities with this protocol.

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A Pd(II)-catalyzed mild and highly regioselective 6- cyclization/alkylation reaction of -(alkynyl)styrenes with simple allylic alcohols has been developed. Under mild reaction conditions, the vinyl palladium species generated in situ after cyclization could insert a C-C double bond of allylic alcohol through a cross-coupling reaction and led to the formation of (alkyl)naphthalenes. This cascade cross-coupling reaction represents a direct and atom economic method for the construction of functionalized naphthalene derivatives in moderate to good yields.

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