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Selective O-difluoromethylation of 1,3-diones using S-(difluoromethyl) sulfonium salt

Chinese Chemical Letters 2019年第8期30卷 1515-1518页

作者： Guo-Kai Liu Xin Li Wen-Bing Qin Wei-Feng Lin Li-Ting Lin Jia-Yi Chen Jian-Jian Liu School of Pharmaceutical Sciences Shenzhen University Health Science Centre Shenzhen University

A facile and highly efficient approach for selective O-difluoromethylation of 1,3-diones by recently developed bench-stable S-(difluoromethyl)sulfonium salt was described.And a broad range of difluoromthyl enol ethers were readily accessed in good to excellent yields under mild reaction conditions.Mechanistic studies revealed that the O-difluoromethylation reaction proceeds mainly via a difluorocarbene pathway.

关键词： Difluorocarbene difluoromethyl enol ethers 1,3-Diones O-difluoromethylation S-(Difluoromethy)sulfonium salt

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Facile synthesis of α-difluoromethyl α-propargylamines from CF_2H-substituted N-tert-butanesulfinyl ketimines

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Chinese Chemical Letters 2012年第3期23卷 277-280页

作者： Hui Chen Wei Yu Xin Hua Guo Wei Dong Meng Yan Gen Huang College of Chemistry Chemical Engineering and BiotechnologyDonghua UniversityShanghai 201620China

Stereoselective approach for preparation ofα-difluoromethylα-propargylamines has been developed.1,2-Addition of lithium acetylides to diverse chiral difluoromethylated（S）-N-tert-butanesulfinyl ketimines by using Ti（O^iPr）_4 as catalyst and THF as solvent afforded N-tert-butanesulfinamides in good to excellent yields（51-93%） and good diastereoselectivities（dr.85：15 to 93：7）.The N-tert -butanesulfinyl group can be readily cleaved under mild acidic condition（4 mol/L HCl in dioxane） to provide the correspondingα-difiuoromethylα-propargylamine in excellent yields（90-95%）.

关键词： Diasteroselectivity difluoromethyl Propargylamine 1 2-Addition Sulfinamides

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An efficient three-component domino synthesis of difluoromethyl-containing 1,4-dihydropyridines under solvent and catalyst free conditions

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Science China Chemistry 2010年第7期53卷 1509-1513页

作者： LI Hui YU JinLong CAO Song SHEN Li WU MingXi CHENG JianHang QIAN XuHong Shanghai Key Laboratory of Chemical Biology Center of Fluorine Chemical TechnologySchool of PharmacyEast China University of Science and TechnologyShanghai 200237China

The difluoromethyl-containing Hantzsch 1,4-dihydropyridines were synthesized in good yields by a one-pot cyclocondensation of ethyl difluoroacetoacetate (EDFAA),a variety of aromatic aldehydes and ammonium acetate under solvent and catalyst free conditions.The comparison of reaction conditions and products was made among the different 1,3-carbonyl substrates (ethyl acetoacetate,ethyl difluoroacetoacetate and ethyl trifluoroacetoacetate) for the Hantzsch reaction.

关键词： three-component difluoromethyl 1,4-dihydropyridines ethyl difluoroacetoacetate

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Ligand-Controlled Copper-Catalyzed Highly Regioselective difluoromethylation of Allylic Chlorides/Bromides and Propargyl Bromides

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Chinese Journal of Chemistry 2018年第1期36卷 55-58页

作者： Yang Gu Changhui Lu Yucheng Gu Qilong Shen Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic Chemistry University of Chinese Academy Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China Syngenta Jealott's Hill International Research Cente Bracknell Berkshire RG42 6EY UK

Highly regiodivergent copper-catalyzed allylic/propargylic difluoromethylation reactions by employing different ligands are described. When 5,6-dimethyl-1,10-phenanthroline was used as the ligand, exclusively α-difluoromethylated products were obtained, while γ-selective difluoromethylated products were generated when N-heterocyclic carbene-SIPr was used as the ligand. Likewise, high α- vs. γ-selectivities were achieved in the presence of similar copper catalysts for the reactions of propargyl bromides. Moreover, a copper-catalyzed asymmetric allylic difluoromethylation reaction with moderate to good enantioselectivity by the use of chiral ligands was developed.

关键词： fluorine difluoromethyl copper asymmetric allylic substitution

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Palladium Difluorocarbene Involved Catalytic Coupling with Terminal Alkynes

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CCS Chemistry 2020年第5期2卷 293-304页

作者： Xue-Ying Zhang Xia-Ping Fu Shu Zhang Xingang Zhang Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200032(China) College of Chemistry Henan Institute of Advanced TechnologyZhengzhou UniversityZhengzhou 450001(China) School of Materials and Energy University of Electronic Science and Technology of ChinaChengduSichuan 611731(China)

difluoromethylated alkynes are a versatile synthon for the diversity-oriented synthesis of difluoromethyl compounds that are of great interest in life and materials sciences.However,the catalytic cross-coupling for the synthesis of difluoromethylated alkynes remains challenging,despite impressive achievements made in the cross-coupling reactions for alkynes,including the Sonogashira reaction.Here,we report a palladium difluorocarbene involvement in catalytic coupling with terminal alkynes,representing a new mode of conjugation reaction,which circumvents the radical pathway usually encountered during the coupling of alkynes with fluoroalkyl electrophiles.The reaction uses inexpensive and abundant industrial raw material chlorodifluoromethane(ClCF_(2)H)as the difluorocarbene precursor,and features cost-effectiveness,excellent functional group tolerance,and broad substrate scope,including synthesis of drug-like complex molecules.Our mechanistic studies showed a unique catalytic pathway of this process,in which additive hydroquinone plays a pivotal role in promoting the reaction.

关键词： Alkynes cross-coupling difluorocarbene difluoromethyl palladium

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