title: Medium-Ring Effects on the Endo/Exo Selectivity of the Organocatalytic Intramolecular Diels-Alder Reaction.
abstract: The intramolecular Diels-Alder reaction has been used as a powerful method to access the tricyclic core of the eunicellin natural products from a number of 9-membered-ring precursors. The endo/exo selectivity of this reaction can be controlled through a remarkable organocatalytic approach, employing MacMillan's imidazolidinone catalysts, although the mechanistic origin of this selectivity remains unclear. We present a combined experimental and density functional theory investigation, providing insight into the effects of medium-ring constraints on the organocatalyzed intramolecular Diels-Alder reaction to form the isobenzofuran core of the eunicellins.
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne , 30 Flemington Road, Melbourne, Victoria 3010, Australia.
authors.forename: Joel F
authors.initials: JF
authors.lastname: Hooper
authors.affiliation: Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.
authors.forename: Natalie C
authors.initials: NC
authors.lastname: James
authors.affiliation: Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland.
authors.forename: Esra
authors.initials: E
authors.lastname: Bozkurt
authors.affiliation: Department of Chemistry, Boğaziçi University , Bebek 34342, Istanbul, Turkey.
authors.forename: Viktorya
authors.initials: V
authors.lastname: Aviyente
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne , 30 Flemington Road, Melbourne, Victoria 3010, Australia.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
authors.affiliation: Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.|Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , 48149 Münster, Germany.
authors.forename: Mareike C
authors.initials: MC
authors.lastname: Holland
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , 48149 Münster, Germany.
authors.forename: Ryan
authors.initials: R
authors.lastname: Gilmour
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne , 30 Flemington Road, Melbourne, Victoria 3010, Australia.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Holmes
authors.affiliation: Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.
authors.forename: K N
authors.initials: KN
authors.lastname: Houk
mesh_terms: D001572:Benzofurans / Q000737:chemistry*; D002384:Catalysis; D061565:Cycloaddition Reaction; D004224:Diterpenes / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D001572:Benzofurans; D004224:Diterpenes; C476503:eunicellin; C105430:benzofuran