An efficient one-pot synthesis of functionalized 2-amino-4H-pyrans by a meglumine-catalyzed three-component reaction has been developed. A broad range of substrates including aromatic and heteroaromatic aldehydes, isatin derivatives, and acenaphthenequinone are condensed with enolizable C-H activated compounds and alkylmalonates to give the desired products in high to excellent yields. This methodology provides an alternative approach for rapid access to construct a diversity-oriented library of 4H-pyrans.
Diammonium Hydrogen Phosphate: An Efficient and Versatile Catalyst for the One‐Pot Synthesis of Tetrahydrobenzo[<i>b</i>]pyran Derivatives in Aqueous Media
Diammonium hydrogen phosphate was used as a mild, efficient, neutral, and cheap catalyst for the synthesis of various 4H-benzo[b]pyran derivatives via a one-pot, three-component condensation of aromatic aldehydes, active methylene compounds, and dimedone in aqueous media.