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Please login or sign up for a free trial to access the full content. Method 35: Synthesis from Alkyl Methylenecyanoacetates or Methylenemalononitriles and Hydroxyarenes, Hydroxyhetarenes, or Enolizable Ketones

DOI: 10.1055/sos-SD-024-00398

Kantlehner, W.Science of Synthesis, (200624383.

A heuristic concept of Birckenbach states that methylenecyanoacetates or methylenemalononitriles should show a reactivity pattern which is comparable to that of the parent carbonyl compounds (aldehydes or ketones). Thus they can electrophilically attack hydroxyarenes, hydroxyhetarenes, or enols of ketone derivatives. The adducts thus formed can cyclize after tautomerization to give ketene O,N-acetals, e.g. 41, by addition of the hydroxy group to the nitrile group in the presence of a catalytic amount of a base (Scheme 80). Methylene derivatives of nitroacetonitrile and (diethoxyphosphono)acetonitrile can also be used.[‌156‌‌204‌] By this reaction principle, several hundred heterocyclic ketene O,N-acetals of a wide structural variety have been prepared.

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