Synthesis of natural quinazolinones and some of their analogues through radical cascade reactions involving N-acylcyanamides

Two natural quinazolinones and two analogues can be prepared from the cascade cyclizations of alkyl-substituted N-acylcyanamide radicals, including 5-exo-dig or 6-exo-dig cyclizations onto the cyano group, followed by radical arylations of the resulting amidyl radicals. The fact that one can carry out the cascades from alkyl radicals in addition to aryl, vinyl and aminyl ones, shows the versatility of the method to rapidly access nitrogen-containing polycyclic structures.