Combined use of Tf2NH and In(OTf)3 effectively promotes the cyclization of alk-5-ynyl ketones to cyclopent-1-enyl ketones at 30 °C. Single use of Tf2NH or In(OTf)3 requires heating at 50 °C for efficient cyclization. The In(OTf)3-promoted reaction of certain alk-5-ynyl ketones gives cyclohept-2-enones mainly.
A novel access to fused furan cores usingsilver oxide(I) has been developed. Mechanistic investigations indicate the involvement of a Conia-ene reaction/radical cyclization for an expedient path to complex furan derivatives. The reaction is broad in scope with interesting atom economy and can also be conducted in a one-pot fashion from readily accessible α,β-unsaturated ketones.
已开发出一种使用氧化银 ( I )获得熔融呋喃芯的新方法。机理研究表明,Conia-ene 反应/自由基环化的参与是获得复杂呋喃衍生物的捷径。该反应范围广泛,具有有趣的原子经济性,也可以从容易获得的 α,β-不饱和酮以一锅方式进行。
TfOH-catalyzed intramolecular alkyne–ketone metathesis leading to highly substituted five-membered cyclic enones
The intramolecular carbocyclization of tethered alkynylketones to five-membered cyclic enones is shown to be catalyzed by trifluoromethanesulfonic acid in MeOH, proceeding in good to excellent yields and with high selectivities.