Recent Advances in the Asymmetric Synthesis of Spiro Compounds Through Cycloadditions

This chapter assesses the most relevant synthetic methodologies toward the asymmetric catalytic construction of spirocyclic compounds by means of either cycloaddition or formal cycloaddition processes published between 2015 and 2019. It discusses the substrate scope, the generality, and limitations as well as the key reaction mechanism. The chapter is divided between organometallic and organocatalytic strategies. The different methodologies are classified according to the number of atoms involved in the formation of the spiro cycle. Transition-metal catalysis has emerged as a powerful tool for the construction of complex molecules. The versatility and robustness of the different organocatalytic activation modes have been implemented in a number of stereoselective cascade processes, addressing the requests of atom and step economy of modern synthetic chemistry. The development of switchable intermolecular reactions that afford divergent reaction pathways is an attractive and powerful strategy to build up structural and stereogenic diversity in drug discovery.