Trifluoromethylthiolation and Trifluoromethylselenolation of α-Diazo Esters Catalyzed by Copper
作者:Christian Matheis、Thilo Krause、Valentina Bragoni、Lukas J. Goossen
DOI:10.1002/chem.201602730
日期:2016.8.22
α‐Diazo esters are smoothly converted into the corresponding trifluoromethyl thio‐ or selenoethers by reaction with Me4NSCF3 or Me4NSeCF3, respectively, in the presence of catalytic amounts of copper thiocyanate. This straightforward method gives high yields under neutral conditions at room temperature and is applicable to a wide range of functionalized molecules, including diverse α‐amino acid derivatives
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
Palladium-Catalyzed Stereoselective Hydrodefluorination of Tetrasubstituted <i>gem</i>-Difluoroalkenes
作者:Qiao Ma、Caroline Liu、Gavin Chit Tsui
DOI:10.1021/acs.orglett.0c01813
日期:2020.7.2
A highly stereoselective palladium(0)-catalyzed hydrodefluorination (HDF) of tetrasubstituted gem-difluoroalkenes is developed. By usingcatalytic Pd(PPh3)4 (2.5–5 mol %) and hydrosilane Me2PhSiH, various trisubstituted terminal (E)-monofluoroalkenes can be synthesized with excellent E/Z selectivity (>99:1) and good functional group tolerability. The key stereocontrol should be exerted by an ester-directed
A Catalytic Asymmetric Ring‐Expansion Reaction of Isatins and α‐Alkyl‐α‐Diazoesters: Highly Efficient Synthesis of Functionalized 2‐Quinolone Derivatives
Asymmetricexpansion: A catalyticasymmetricring‐expansionreaction of the title compounds occurs in the presence of a Sc(OTf)3 catalyst bearing an N,N′‐dioxide‐based ligand. Highlyfunctionalized2‐quinolonederivatives containing a chiral C4‐quaternary stereocenter were obtained in high yields and high levels of selectivity under mild reaction conditions (see scheme; Tf=trifluoromethanesulfonyl)
Palladium-Catalyzed Stereoselective Defluorosilylation of <i>gem</i>-Difluoroalkenes for the Synthesis of Tetrasubstituted Monofluorinated Vinylsilanes
作者:Yuwei Zong、Ziwei Luo、Gavin Chit Tsui
DOI:10.1021/acs.orglett.3c00718
日期:——
Stereoselectivesynthesis of tetrasubstituted vinylsilanes is a challenging task. We herein report a novel palladium(0)-catalyzed defluorosilylation of β,β-difluoroacrylates to access tetrasubstituted vinylsilanes containing the monofluoroalkene motif in excellent diastereoselectivities (>99:1). This is our first example of C–heteroatom bond formation from the C–F bond under such a Pd catalytic manifold