Photoredox- and piezo-catalysed access to complex trifluoromethylated polycyclic structures from ynamides

Radical cyclization cascades triggered by a trifluoromethyl radical represent a valuable tool for accessing highly complex and biologically relevant scaffolds. Herein, we introduce a strategy employing ynamides as pivotal functions for the diastereoselective synthesis of gamma-lactam polycyclic compounds incorporating a trifluoromethyl group. Using photoredox conditions, this cascade featuring notably a 1,5 hydrogen atom transfer proceeds with high efficiency and diastereoselectivity. Additionally, a mechanoredox approach utilizing piezocatalysis proved to be competent in providing the same highly functionalized polycyclic products. Under photoredox- and piezo-catalysis conditions, ynamides undergo a radical to yield polycyclic compounds by fully utilizing the ynamide unsaturations.