Table 2.

Substrate scopes for the synthesis of 2-amino-3-cyano-4H-chromenes derivatives 4a–t.

Reaction condition: Aldehyde 1a-o (1.0 mmol), malononitrile 2a (1.0 mmol), and 5,5-dimethylcyclohexane-1,3-dione 3a/cyclohexane-1,3-dione 3b (1.0 mmol) in the presence of 10 mol% of TsOH⋅H₂O in H₂O (η = 0.35 μL/mg) as LAGs [η = V (liquid; μL)/m (reagents; mg)] at ambient temperature. *Isolated yield.