Access to Fully Substituted Furans via Boryl Radical Catalyzed Cycloisomerization of Cyclopropenyl Ketones

We report the boryl radical catalyzed cycloisomerization of cyclopropenyl ketones to fully‐substituted furans, a type of highly important pharmacophore and synthetic intermediate. The reaction features neutral conditions, high yields and toleration of variation at all possible positions of the substrate, making it an indispensable route for this type of important scaffold. Preliminary downstream transformation also revealed the synthetic potential of these furans in accessing other types of furans or more complex three‐dimensional scaffolds.