Fig. 1: Reaction background and our discovery.

A Biologically relevant and electrochromic motifs containing pentafulvenes. B Metal catalyzed enantioselective homologation of cycloalkanones. C Asymmetric vinylogous desymmetrizing annulation of cycloalkanones. D Reaction design for H-bond catalyzed desymmetrizing (4 + 2) annulation. E Asymmetric vinylogous enantioselective homologating annulation between cyclopent-4-ene-1,3-dienone and 3-cyano-4-methylcoumarin.