Metal-free catalytic de novo construction of multi-functionalized trifluoromethylarenes through [3 + 3] benzannulation at low catalyst loadings†

A low catalyst loading and transition metal-free benzannulation of β,γ-alkynyl-α-keto esters and CF₃-alkenes has been developed through Michael-triggered [3 + 3] annulation. The newly developed methodology provides highly efficient and rapid access to a variety of multi-functionalised trifluoromethylarene derivatives in generally good to excellent yields. The late-stage functionalisation of some natural products and bioactive molecules and the gram-scale reaction as well as transformation of the products indicate that the present protocol has significant practical value and reliability.