title: Radical and palladium-catalyzed cyclizations to cyclobutenes: an entry to the BCD ring system of penitrem D.
abstract: A novel approach toward the synthesis of the BCD ring system of penitrem D is described. The strategy capitalizes on the fast cyclization rates of aryl radicals into cyclobutenes and allows access to a variety of fused tricyclic structures. Radical/polar crossover reactions of precursors 24-29 promoted by samarium diiodide in the presence of HMPA and acetone allow access to the fully functionalized BCD ring system of penitrem D. The stereochemical implications of these processes are evaluated, and a Pd-mediated cyclization approach toward the penitrems is also introduced.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: Alexey
authors.initials: A
authors.lastname: Rivkin
authors.forename: Felix
authors.initials: F
authors.lastname: González-López de Turiso
authors.forename: Tadamichi
authors.initials: T
authors.lastname: Nagashima
authors.forename: Dennis P
authors.initials: DP
authors.lastname: Curran
mesh_terms: D002384:Catalysis; D003500:Cyclization; D003503:Cyclobutanes / Q000138:chemical synthesis*; D005609:Free Radicals / Q000737:chemistry; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D009183:Mycotoxins / Q000138:chemical synthesis*; D010165:Palladium / Q000737:chemistry*
chemical_list: D003503:Cyclobutanes; D005609:Free Radicals; D009183:Mycotoxins; C003626:tremortin; D010165:Palladium