title: Photochemistry of o-pyrrolylstilbenes and formation of spiro-2H-pyrroles and their rearrangement to dihydroindoles.
abstract: Excited states of stilbenylpyrroles 1a-1c deactivate by two photochemical processes: cis-trans-isomerization and hydrogen transfer of NH to the stilbene double bond. NH-transfer results in the formation of two quinone dimethane intermediates, 10 and 11, and biradicals 12. Intramolecular cyclization of intermediates 10-12 gives rise to polycyclic compounds spiro-2H-pyrroles 7, pyrroloisoindoles 3, and pyrroloisoquinolines 8. Spiro-2H-pyrroles 7 rearrange on silica gel, giving dihydroindoles 2.
authors.affiliation: Division of Organic Chemistry and Biochemistry, and NMR Center, Institute Ruder Boskovic, Bijenicka cesta 54, 10,000 Zagreb, Croatia. mbasaric@irb.hr
authors.forename: Nikola
authors.initials: N
authors.lastname: Basarić
authors.forename: Eljko
authors.initials: E
authors.lastname: Marinić
authors.forename: Marija
authors.initials: M
authors.lastname: Sindler-Kulyk