Visible-light photoredox catalyzed synthesis of polysubstituted furfuryl trifluoroacetamide derivatives

A visible-light photoredox catalyzed reaction of enynones with 2,2,2-trifluoroacetamide to access polysubstituted furfuryl trifluoroacetamide derivatives under mild reaction conditions is reported. This transformation proceeds through the furan-substituted carbene intermediate, which subsequently undergoes an intermocular trapping process by 2,2,2-trifluoroacetamide to produce the desired furfuryl trifluoroacetamides.     

Cu(II)-catalyzed one-pot synthesis of fully substituted dihydrothiophenes and thiophenes from thioamides and enynones

A facile and direct synthetic method was developed for the construction of fully substituted dihydrothiophenes, which via a copper-catalyzed Michael addition/intramolecular cyclization/protonation cascade reaction of readily available thioamides with enynones under air atmosphere. This approach provides 2,3-dihydrothiophenes with up to 92% yield in a one-pot process. In addition, several fully substituted thiophenes could also be synthesized by changing the substituents of thioamides.