A New Route for the Preparation of Substituted 2,2-Difluorostyrenes and a Convenient Route to Substituted (2,2,2-Trifluoroethyl)benzenes
摘要:
The (2,2-difluoroethenyl)zinc reagent II is coupled with aryl iodides or bromides in the presence of Pd(PPh3)(4) in DMF to give the corresponding 2,2-difluorostyrenes IV. The 4-substituted (tetrafluoroaryl)copper reagents are coupled with 2,2-difluoro-1-iodoethylene (I) to produce the corresponding styrene derivatives VII. Both methods provide good yields of the coupled products. These products react with wet KF in DMF or DMSO to form the (2,2,2-trifluoroethyl)benzene derivatives VIII in good yields.
reported. By taking advantage of the in situ generated α-CF3-benzylsilver intermediates derivedfrom the nucleophilic addition of silver fluoride to gem-difluoroalkenes, this strategy bypasses the use of a strong base, thus enabling a mild and general synthetic method for ready access to non-symmetric α,α-disubstituted trifluoroethane derivatives.
which otherwise are essentially reluctant towards F‐nucleoplilic addition, now readily participate in this fluoroallylation reaction. Furthermore, this strategy provides an elegant example for the generation, as well as functionalization, of α‐CF3‐substituted benzylic radical intermediates using cheap and readily available starting materials.
Radical Hydroboration and Hydrosilylation of <i>gem</i>-Difluoroalkenes: Synthesis of α-Difluorinated Alkylborons and Alkylsilanes
作者:Xiaozu Liu、E Emily Lin、Guojun Chen、Ji-Lin Li、Peijun Liu、Honggen Wang
DOI:10.1021/acs.orglett.9b03218
日期:2019.10.18
This protocol features good functional group tolerance, operational simplicity, high atom economy, and easy scale-up, enabling efficient assembly of a wide range of α-difluorinated alkylborons and alkylsilanes in moderate to excellent yields. The synthetic utility of these products is demonstrated by further transformation of the C–B bond and C–Si bond into valuable CF2-containing molecules.
Nucleophilic Substitution of <i>gem</i>-Difluoroalkenes with TMSNu Promoted by Catalytic Amounts of Cs<sub>2</sub>CO<sub>3</sub>
作者:Ling-Feng Jiang、Bing-Tao Ren、Bin Li、Guang-Yi Zhang、Yi Peng、Zhen-Yu Guan、Qing-Hai Deng
DOI:10.1021/acs.joc.9b00999
日期:2019.6.7
The efficient and practical nucleophilic cyanation and trifluoromethylation with appropriate trimethylsilyl nucleophiles were developed. Catalytic amounts of cheap and nontoxic Cs2CO3 were used to maintain a sufficiently high concentration of nucleophilic anion (CN– or CF3–) which could begin the catalytic cycle. The present methodologies provide diverse functionalized monofluoroalkenes bearing a cyano
开发了有效和实用的亲核氰化和三氟甲基化反应以及适当的三甲基甲硅烷基亲核试剂。廉价和无毒性的Cs的催化量的2 CO 3被用来维持亲核阴离子(CN的足够高的浓度-或CF 3 - ),其可以开始催化循环。本方法提供了带有氰基和三氟甲基的各种官能化的单氟烯烃,具有优异至中等的立体选择性。
Stereoselective Rhodium(I)-Catalyzed C–F Bond Arylation of Tri- and Tetrasubstituted <i>gem</i>-Difluoroalkenes with Boronic Acids
作者:Hao Tan、Yuwei Zong、Yihan Tang、Gavin Chit Tsui
DOI:10.1021/acs.orglett.3c00108
日期:2023.2.10
We herein describe a highly diastereoselective rhodium(I)-catalyzed C–F bond functionalization of gem-difluoroalkenes with arylboronic acids. In contrast to previously developed Pd(II)- and Pd(0)-catalyzed methods, the Rh(I)/BINAP catalytic system enabled the C–F bond arylation of both trisubstituted β,β-difluorostyrenes and tetrasubstituted β,β-difluoroacrylates in >99:1 dr toward the synthesis of