Synthesis of Bench-Stable Quaternized Ketene ,-Acetals and Preliminary Evaluation as Reagents in Organic Synthesis.

-Quaternized ketene ,-acetals are typically an unstable, transient class of compounds most commonly observed as reactive intermediates. In this report, we describe a general synthetic approach to a variety of bench-stable -quaternized ketene ,-acetals via treatment of pyridine or aniline bases with acetylenic ethers and an appropriate Brønsted or Lewis acid (triflic acid, triflimide, or scandium(III) triflate). The resulting pyridinium and anilinium salts can be used as reagents or synthetic intermediates in multiple reaction types.