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-2H-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-2H-pyrans from the commercially available starting
materials in acceptable yields.

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