Accessing Functionalized Furans from Reacting Enynones and Enynals through Furyl Metal Carbenes

Abstract Enynones and enynals represent donor‐type carbene precursors that efficiently form furyl metal carbenes via a catalytic intramolecular 5‐exo‐dig cyclization and rearrangement cascade, in a 100 % atom‐economical manner, using various metals. These furyl metal carbenes have been successfully utilized in numerous carbene reactions, including metal carbene X−H insertion, cyclopropanations, metathesis, and cross‐coupling, demonstrating a broad reaction scope and efficiency in constructing highly functionalized furans. Recent years have witnessed significant advancements in transformations involving furyl metal carbenes, especially in asymmetric carbene insertion reactions, domino reactions involving zwitterionic intermediates, various rearrangement strategies, and their application in synthesizing functional materials and drug candidates. In this review, we summarize recent progress in furyl metal carbene reactions generated from enynones and enynals, focusing on the synthesis of highly functionalized furans.