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An efficient, rapid, one-pot synthesis of tetrahydrobenzo[b]pyran is achieved via a three-component reaction of aldehydes, 1,3-diketone, malononitrile in 20% ethanol using anhydrous potassium phosphate as a catalyst at room temperature. The key advantages are the short reaction time, high yields, simple work-up, inexpensive catalyst and purification of products by non-chromatographic methods, i.e. by simple recrystallization from ethanol.

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The entitled organocatalyst is non‐toxic, cheap, bio‐degradable and easy to handle, and is used in the synthesis of pyran‐annulated heterocycles for the first time.

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o-Aminoaryl ketones underwent smooth condensation with a variety of α-methylene ketones in the presence of NaHSO 4 .silica gel as a solid acid catalyst to afford 1,2,3-trisubstituted quinolines in excellent yields. The reusability of the catalyst has made the protocol simple, cost-effective and environmentally benign.

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