Non-catalytic solvent-free synthesis of 5,6,7,8-tetrahydro-4H-chromenes from aldehydes, dimedone and malononitrlie at ambient temperature

Non-catalytic solvent-free assembling of aldehydes, dimedone and malononitrile at ambient temperature affords substituted 5,6,7,8-tetrahydro-4H-chromenes in 88-98% yields.