Silver-Catalyzed Regioselective Oxacyclization of 3-Alkynyl Pyrroles: Straightforward Route to 2,3,5-Triarylated Pyrano[3,4- <i>b</i> ]Pyrrolones

We present a method for the silver-catalyzed oxacyclization of 3-alkynylpyrroles to create the pyrano[3,4-<i>b</i>]pyrrolone scaffold. This method exhibits high regioselectivity, enabling position-specific functionalization of the pyrrole core without the need for <i>N</i>-protection. It is also compatible with a broad range of substrates. Using this strategy, we synthesized a small library of novel triarylated pyranopyrroles, thereby enabling the creation of substitution patterns that were previously challenging to achieve. This methodology, therefore, provides a versatile approach to heteroaromatic architectures that are potentially relevant in drug discovery and chemical biology.