Recent advances in skeletal construction strategies and late-stage functionalization in the synthesis of natural triterpenoids

Natural triterpenoids represent a prominent class of secondary metabolites widely distributed in terrestrial plants and marine organisms. Characterized by intricate polycyclic architectures, these compounds exhibit a diverse array of significant biological activities that have garnered sustained research interest in both organic synthesis and medicinal chemistry communities. The strategic implementation of skeletal construction and late-stage functionalization methodologies have emerged as cornerstones in natural product synthesis. These approaches are frequently coupled with high-efficiency chemical transformations, including but not limited to electrocyclic processes, cycloaddition reactions, polyene cyclization cascades, skeletal rearrangements, and late-stage C(sp³)-H oxidations. Such innovative strategies have not only facilitated the total syntheses of complex triterpenoid but also significantly advanced the development of triterpenoid chemistry. This comprehensive review systematically examines the methodological breakthroughs and synthetic applications of skeletal construction tactics and late-stage functionalization in triterpenoid synthesis over the past decade.