New spirolactams of formula (I) having a benzodienone moiety and a azetidinone moiety which are highly stable due to pi interactions. They are useful as UV absorbers and as synthetic intermediates.
New spirolactams of formula (I) having a cycloexadienone moiety which are highly stable due to pi interactions between the W group and the dienone moiety. They are useful as UV absorbers and as intermediates for the synthesis of active biomolecules.