We are interested in development of the applications of alkynes in the synthesis of carboand heterocyclic compounds via their annulation with high-atom utilization and step-economy. In this presentation, we would like to report the recently developed protocols for the synthesis of natural products such as Precocene I (from Ageratum houstonianum), Cassiarin C (from Cassia siamea) from the cyclocondensation of alkynes with the activation of C-H bonds, and the synthesis of the drugs such as h5-HT2A antagonist and RITA. These synthetic protocols have the significant advantages of easily available starting materials, efficient and stepeconomic processes. Polycyclic scaffolds are omnipresent in natural products and drugs, and the synthetic strategies and methods toward the construction of these scaffolds are of particular importance. Compared to simple cyclic ring systems, polycyclic scaffolds have higher structure complexity and diversity, making them suitable for charting broader chemical space, yet bringing challenges for the syntheses. In this review, we surveyed progress in the past decade on synthetic methods for polycyclic natural product scaffolds, in which the key steps are one-pot reactions involving intermolecular or intramolecular alkyne annulation,
