Unraveling complexity: advances in metal-catalyzed sequential double hydrofunctionalization of alkynes.

Sequential double hydrofunctionalization of alkynes (SDHFA) represents an atom- and pot-economical strategy to access geminal- and vicinal-difunctionalized compounds, which are widespread in drug molecules, bioactive natural products, and functional polymers and materials. However, the multiple-step nature of SDHFA brings more challenges associated with chemo-, regio- and stereoselective control; meanwhile, the one-pot setting may introduce incompatibility between the two steps. Metal catalysis has played an important role in modern organic chemistry, and various catalytic systems have been applied to solve the above-mentioned challenges. Over the past decades, considerable advances have been made in metal-catalyzed SDHFA. This review provides a comprehensive summary of this field, covering the addition reactions of O-H, N-H, C-H, P-H, S-H, B-H, and Si-H bonds, and highlights representative mechanisms and synthetic applications with the aim of providing useful insight into this area and promoting its further development.