An efficient procedure for the synthesis of functionalized 3,4-dihydro-2H-pyrans via catalytic multicomponent reaction

In this transformation, conjugated base of malonitrile was reacted with reactive nitrilium ion derived from the reaction of isocyanides and oxiranes in the presence of lithium salts in PEG-400. The reaction was successfully utilized to synthesize 3,4-dihydro-2 H -pyrans in accordance with a simple and environmentally benign procedure. The optimized reaction conditions allowed the selective synthesis of the highly functionalized 3,4-dihydro-2 H -pyrans from the commercially available starting materials in acceptable yields. Graphical abstract