methods for the convergent synthesis of (poly)cyclic scaffolds are urgently needed in synthetic and medicinal chemistry. Herein, we describe new annulation reactions of thioalkynes with phthalimide‐substituted donor–acceptor cyclopropanes, which gave access to highly substituted cyclopentenes and polycyclic ring systems. With silyl‐thioalkynes, the Lewis acid catalyzed [3+2] annulation reaction with