Pd-Catalyzed α-Arylation of α,α-Difluoroketones with Aryl Bromides and Chlorides. A Route to Difluoromethylarenes
作者:Shaozhong Ge、Wojciech Chaładaj、John F. Hartwig
DOI:10.1021/ja501117v
日期:2014.3.19
α-difluoroketones with aryl and heteroaryl bromides and chlorides catalyzed by an air- and moisture-stable palladacyclic complex containing P(t-Bu)Cy2 as ligand. The combination of this Pd-catalyzed arylation and base-induced cleavage of the acyl–aryl C–C bond within the α-aryl-α,α-difluoroketone constitutes a one-pot, two-step procedure to synthesize difluoromethylarenes from aryl halides. A broad range
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
An acid-mediated selective cleavage of C–C doublebond of N-(2-hydroxylphenyl)enaminones with formation a new C–O bond for the synthesis of 2-substituted benzoxazoles has been developed. This protocol proceeds under transition metal- and oxidant-free conditions with broad functional group tolerance. The oxidative cleavage of C–C doublebond of N-(2-hydroxylphenyl)enaminone is also realized using NCS
Redox-Neutral 1,3-Diol Synthesis by Base-Promoted Diastereoselective Alcohol–Aldolization
作者:Na Shao、Jean Rodriguez、Adrien Quintard
DOI:10.1021/acs.orglett.0c02536
日期:2020.9.18
redox-neutral condensation of ketones with alcohols. This diastereoselective alcohol–aldolization enables bypassing the classical oxidation and reduction steps necessary for the preparation of this crucial backbone by an overall redox-neutral formal borrowing hydrogen process. The starting alcohols constitute both the precursors of the in situ generated reactive aldehydes and the hydride source necessary