Alkyne oxidation chemistry, pioneered in Au and Rh catalysis, has enables access to α-oxo carbene synthons and thereby mediates a variety of C-X bond formations, C-H functionalizations and cyclopropanations. In this presentation, we report a simple and robust strategy to access α-oxo carbene equilvalent under Brönsted acid catalysis. Inspired with pioneering work on acid-catalyzed generation of keteniminium ions by Hsung and Kozmin as well as transition metal-catalyzed α-oxo carbene chemistry, we envisioned Brønsted acid catalyzed ‘enolate umpolung’ strategy for intermolecular coupling of ynamide with different nucleophiles, that would result in α,α-di(hetero)aryl amide which are one of the most widely occurring structural motifs in various biologically active compounds, natural products, and electro-optical materials. It is intriguing because such non-metal approach has been limited only to intramolecular cases so far, because an intermolecular version requires chemoselective differentiation of possible nucleophilic species. We found that easily available ynamides can serve as an excellent substrates in the presence of catalytic amount of Brönsted acid giving keteniminium ions, followed by N-oxide attack and intermolecular Friedel Craft addition to the umpolung enolate, with remarkable ease (RT, 1~2 h) (Eq. 1). This simple yet robust synthetic methodology is applicable to wide range of nucleophiles such as indoles, pyrroles, phenols and silyl-enol ethers in good to excellent yields (45-98 %).