<i>gem-</i>Difluoroolefination of Diazo Compounds with TMSCF<sub>3</sub> or TMSCF<sub>2</sub>Br: Transition-Metal-Free Cross-Coupling of Two Carbene Precursors
作者:Mingyou Hu、Chuanfa Ni、Lingchun Li、Yongxin Han、Jinbo Hu
DOI:10.1021/jacs.5b09888
日期:2015.11.18
fragment resulting from a diazocompound and a difluorocarbene fragment derived from Ruppert-Prakash reagent (TMSCF3) or TMSCF2Br, has been developed. This gem-difluoroolefination proceeds through the direct nucleophilic addition of diazocompounds to difluorocarbene followed by elimination of N2. Compared to previously reported Cu-catalyzed gem-difluoroolefination of diazocompounds with TMSCF3, which possesses
Stereoselective Palladium‐Catalyzed C−F Bond Alkynylation of Tetrasubstituted
<i>gem</i>
‐Difluoroalkenes
作者:Qiao Ma、Yanhui Wang、Gavin Chit Tsui
DOI:10.1002/anie.202002219
日期:2020.7.6
A stereoselective Pd(PPh3)4‐catalyzed C−F bond alkynylation of tetrasubstituted gem ‐difluoroalkenes with terminal alkynes has been developed. This method gives access to a great variety of conjugated monofluoroenynes bearing a tetrasubstituted alkene moiety with well‐defined stereochemistry. Chelation‐assisted oxidative addition of Pd to the C−F bond is proposed to account for the high level of stereocontrol
Stereoselective Synthesis of Difluorinated 1,3-Dienes via Palladium-Catalyzed C–F Bond Activation of Tetrasubstituted <i>gem</i>-Difluoroalkenes
作者:Yanhui Wang、Qiao Ma、Gavin Chit Tsui
DOI:10.1021/acs.orglett.1c01768
日期:2021.7.2
Pd(0)-catalyzed synthesis of difluorinated 1,3-dienes is described. Symmetrical 1,3-dienes containing a vicinal difluoro moiety can be obtained as single diastereomers from tetrasubstituted gem-difluoroalkenes. The reaction presumably proceeds through a stereoselective twofold Pd-catalyzed Miyaura borylation/Suzuki–Miyaura cross-coupling of the C–F bond. Moreover, modular synthesis of unsymmetrical
Nucleophilic Vinylic Substitution (S<sub>N</sub>V) of Trisubstituted Monofluoroalkenes for the Synthesis of Stereodefined Trisubstituted Alkenes and Divinyl Ethers
作者:Yuwei Zong、Qiao Ma、Gavin Chit Tsui
DOI:10.1021/acs.orglett.1c02359
日期:2021.8.6
We herein describe a nucleophilic vinylic substitution (SNV) of trisubstituted monofluoroalkenes with excellent stereocontrol (d.r. > 99:1). Starting from (E)-β-monofluoroacrylates, various trisubstituted (E)-alkenes containing O/N/S-substituent groups at the vinylic position can be obtained under simple conditions. Furthermore, (E,E)-divinyl ethers can be generated through dimerization of the monofluoroalkenes
我们在此描述了三取代的单氟烯烃的亲核乙烯基取代 (S N V),具有出色的立体控制 (dr > 99:1)。以( E )-β-单氟丙烯酸酯为原料,在简单的条件下,可以得到在乙烯基位置含有O/N/S-取代基的各种三取代( E )-烯烃。此外,( E,E )-二乙烯基醚可以通过单氟烯烃的二聚作用产生,由反应混合物中的外来水引发。
Palladium-Catalyzed Stereoselective C−F Bond Vinylation and Allylation of Tetrasubstituted <i>gem</i>-Difluoroalkenes via Stille Coupling: Synthesis of Monofluorinated 1,3- and 1,4-Dienes
作者:Min Li、Yanhui Wang、Gavin Chit Tsui
DOI:10.1021/acs.orglett.1c03096
日期:2021.10.15
We herein describe a Pd-catalyzed stereoselective C−F bond vinylation and allylation reaction of tetrasubstituted gem-difluoroalkenes for the synthesis of valuable monofluorinated 1,3- and 1,4-dienes with excellent diastereoselectivities. Different from previously used Pd(PPh3)4, a catalytic system involving Pd(0) and dppe as the ligand was developed for Stille-type cross-coupling between gem-difluoroalkenes