Synthesis of substituted 2-amino-3-cyanodihydrofurans from styrene oxides and malononitrile

The reaction of styrene oxides with the malononitrile anion leads to the formation of 2-amino-3-eyano-5-aryl-4,5-dihydrofurans (III), while a similar reaction with β,β-dimethylstyrene oxides leads to 2-amino-3-cyano-4-aryl-5,5-dimethyI-4,5-dihydrofurans (V). Therefore steric factors may play a significant role in the site of attack of the malononitrile anion on the oxide. Compounds of type V are more conveniently obtained from the cyanolaetones (VI) by rearrangement and dehydration.