2‐Alkynylbenzaldehyde: A Versatile Building Block for the Generation of Cyclic Compounds

Abstract The extensive use of cyclic compounds in many fields encourages the efficient construction of this class of compounds. Tandem reactions provide easy access to cyclic compounds because of their simple procedures, high efficiency, and superior atom economy. 2‐Alkynylbenzaldehyde is a versatile and powerful building block for generating functionalized polycyclic compounds, especially heterocycles, by tandem reactions. This Focus Review discusses recent advances in using 2‐alkynylbenzaldehydes as starting materials in the preparation of diverse and complex cyclic compounds. The progress that has been made provides important protocols for the design of more complex compounds and total syntheses of natural products.