Recent advances in post Ugi-4CR dearomatizations for constructing spiro heterocycles

The Ugi reaction has obtained broad interest due to mild reaction conditions and high variability. The Ugi adducts provide myriad opportunities for post-transformations, leading to heterocycles, bioactive molecules, macrocycles, polymers, natural products and drugs. Recently, dearomatization strategies have been employed in post-Ugi transformations. Through transition metal catalysis and metal-free methods, different kinds of three dimensional complex molecules are formed in an atom- and step-economic manner. This review summarizes recent advances in the combination of the Ugi-4CR and dearomatization strategies for the synthesis of spirocycles.