Modular Approach to Substituted Boc-Protected 4-(Aminomethyl)pyrroles

The radical addition of various α-xanthyl ketones to Boc-protected azetine gives adducts which, when treated with ammonia or primary amines, furnish 2,4-disubstituted, 2,3,4-trisubstituted, and polycyclic pyrroles having a protected aminomethyl group at position 4. An unusual ring-opening was observed in the case of a cyclobutanone precursor.