Synthesis of Difluoromethyl Ketones from Weinreb Amides, and Tandem Addition/Cyclization of <i>o</i>
-Alkynylaryl Weinreb Amides
作者:Jongkonporn Phetcharawetch、Nolan M. Betterley、Darunee Soorukram、Manat Pohmakotr、Vichai Reutrakul、Chutima Kuhakarn
DOI:10.1002/ejoc.201701322
日期:2017.12.15
[Difluoro(phenylsulfanyl)methyl]trimethylsilane (PhSCF2SiMe3) underwent a fluoride-induced nucleophilic addition to the carbonyl group of Weinreb amides to provide the corresponding difluoro(phenylsulfanyl)methyl ketones. These were converted into difluoromethyl ketones through selective reductive cleavage of the phenylsulfanyl group. The reaction of o-alkynyl Weinreb amides derived from benzoic acid derivatives resulted
Direct and Chemoselective Synthesis of Tertiary Difluoroketones via Weinreb Amide Homologation with a CHF<sub>2</sub>-Carbene Equivalent
作者:Margherita Miele、Andrea Citarella、Nicola Micale、Wolfgang Holzer、Vittorio Pace
DOI:10.1021/acs.orglett.9b03024
日期:2019.10.18
Weinreb amides into difluoromethylketones with a formal nucleophilic CHF2 transfer agent is reported. Activating TMSCHF2 with potassium tert-amylate enables a convenient access to the difluorinated homologation reagent, which adds to the acylating partners. The high chemoselectivity showcased in the presence of variously multifunctionalized Weinreb amides, jointly with uniformly high yields, enables the
Catalytic Enantioselective Synthesis of Highly Functionalized Difluoromethylated Cyclopropanes
作者:Maxence Bos、Wei-Sheng Huang、Thomas Poisson、Xavier Pannecoucke、André B. Charette、Philippe Jubault
DOI:10.1002/anie.201707375
日期:2017.10.16
The first catalyticasymmetricsynthesis of highly functionalized difluoromethylated cyclopropanes is described. The method, based on a rhodium‐catalyzed cyclopropanation of difluoromethylated olefins, gives access to a broad range of cyclopropanes bearing ester, ketone, or nitro functional groups. By using Rh2((S)‐BTPCP)4 as a catalyst, the corresponding products were obtained in high yields and high
Visible light-promoted umpolung coupling of aryl tri-/difluoroethanones with 2-alkenylpyridines
作者:Xiao Xu、Qing-Qiang Min、Na Li、Feng Liu
DOI:10.1039/c8cc06748a
日期:——
Tertiaryalcohols bearing a trifluoromethyl group are of considerable medicinal interest. Using an umpolung strategy, we herein report the first intermolecular reductive cross-coupling of aryl tri-/difluoroethanones with 2-alkenylpyridines with the aid of a Brønsted acid catalyst upon visible-light irradiation. This metal-free reaction is operationally simple and performed at ambient temperature, allowing
Internally Reuse Waste: Catalytic Asymmetric One-Pot Strecker Reaction of Fluoroalkyl Ketones, Anilines and TMSCN by Sequential Catalysis
作者:Yun-Lin Liu、Xiao-Ping Yin、Jian Zhou
DOI:10.1002/cjoc.201800001
日期:2018.4
enantioselective one‐pot facile synthesis of fluorinated Cα‐tetrasubstituted amino nitriles from α‐fluoroalkyl α‐aryl ketones, anilines, and TMSCN through a sequential p‐TsOH catalyzed ketimine formation and chiral bifunctional tertiaryamine mediated asymmetric Strecker reaction. This one‐pot approach has two important advantages. First, it greatly improves the overall yield of the synthesis of chiral Cα‐tetrasubstituted