One-Pot Transformation of Silyl Enol Ethers into 1,3-Dienes: In situ Generation of Alkenyl Nonaflates and Subsequent Heck Reactions − Scope and Limitations
作者:Ilya M. Lyapkalo、Matthias Webel、Hans-Ulrich Reißig
fluoride-promoted exchange of the trimethylsilyl substituent of typical enol ethers 1 for a nonafluorobutylsulfonyl group was directly combined with the palladium-catalysed coupling step. This sequence allowed the efficient transformation of a variety of silyl enol ethers 1 into highly substituted 1,3-dienes in a practical one-pot procedure. The scope and limitations, together with the chemo- and stereoselectivity
Radical Desulfur‐Fragmentation and Reconstruction of Enol Triflates: Facile Access to α‐Trifluoromethyl Ketones
作者:Xiaolong Su、Honggui Huang、Yaofeng Yuan、Yi Li
DOI:10.1002/anie.201608507
日期:2017.1.24
efficient oxidative radical desulfur‐fragmentation and reconstruction of enoltriflates for the synthesis of α‐CF3 ketones. Preliminary mechanistic studies disclosed that oxidative fragmentation to release a CF3 radical from the triflyl group of enoltriflate and subsequent addition of the CF3 radical to another enoltriflate form the desired α‐CF3 ketones. This method provides a new approach to α‐CF3
Three-Component Bisannulation for the Synthesis of Trifluoromethylated Tetracyclic <i>Aza</i>-Aromatics through Six C(sp<sup>3</sup>)–F Bond Cleavage and Four C–N Bond Formation
unprecedented and expeditious tandem bisannulation of polyfluoroalkylated tetralones with benzamidines to access various fluoroalkyl tetracyclic [1,3]-diazepines through multiple C–N bondformation and C(sp3)–F bond cleavage is reported. The process features high regio-/chemoselectivities, broad substrate scope, good functional group tolerance, procedural simplicity, mild reaction conditions, and scale-up
Polycyclic heteroaromatic ring construction driven by silver/cobalt co-catalyzed desulfonylative and defluorinative fragment-recombination of enol nonaflates with amidines
A novel Ag(i)/Co(ii) co-catalyzed tandem fragmentation and recombination reaction commencing from detachable nonaflates and amidines has been developed.
catalysts for this process. The reaction allows the synthesis of a wide variety of cyclic and acyclic alkenyl nonaflates 3 in good to excellent yields. For E/Z isomeric alkenes the configuration of the double bond is essentially retained. Remarkably, enolates derived from methyl ketones also provide C-sulfonylation products 4 as a side product; the desired alkenyl nonaflates 3l and 3m could, however, be prepared