Recent Advances in Construction of Polycyclic Natural Product Scaffolds via One-Pot Reactions Involving Alkyne Annulation

Polycyclic scaffolds are omnipresent in natural products and drugs, and the synthetic strategies and methods towards 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, but also resulting challenges for the syntheses. In this review, we surveyed progress in the past decade on synthetic methods for polycyclic scaffolds that present in or closely related to natural products, in which the key steps are one-pot reactions involving inter- or intramolecular alkyne annulation. Synthetic strategies of selected polycyclic carbocycles and heterocycles which having at least three fused, bridged or spiro rings are discussed with emphasis on the synthetic efficiency and product diversity. Recent examples containing newly developed synthetic concepts or toolkits such as collective and divergent total synthesis, gold catalysis, C–H functionalization and dearomative cyclization are highlighted. Finally, several “privileged synthetic strategies” for “privileged polycyclic scaffolds” are summarized, with discussion of remained challenges and future perspectives.