title: Iron(III) Chloride Catalyzed Formation of 3,4-Dihydro-2H-pyrans from α-Alkylated 1,3-Dicarbonyls. Selective Synthesis of α- and β-Lapachone.
abstract: A mild, catalytic method for the synthesis of 3,4-dihydro-2H-pyrans is described. The FeCl3-catalyzed transformation of aryl- and alkyl β-diketones enables synthetic access to functionalized pyran core structures incorporated in many natural products and biologically active target structures. The method represents a mild alternative to currently available reaction protocols relying on stoichiometric reagents and harsh reaction conditions. This FeCl3-catalyzed transformation has enabled the selective synthesis of α-lapachone in two synthetic transformations and subsequently β-lapachone in three synthetic transformations, which is currently undergoing clinical trials as a potent anticancer agent.
authors.affiliation: University of Michigan , Department of Chemistry, Willard Henry Dow Laboratory, 930 North University Avenue, Ann Arbor, Michigan 48109, United States.
authors.forename: Rebecca B
authors.initials: RB
authors.lastname: Watson
authors.affiliation: University of Michigan , Department of Chemistry, Willard Henry Dow Laboratory, 930 North University Avenue, Ann Arbor, Michigan 48109, United States.
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Golonka
authors.affiliation: University of Michigan , Department of Chemistry, Willard Henry Dow Laboratory, 930 North University Avenue, Ann Arbor, Michigan 48109, United States.
authors.forename: Corinna S
authors.initials: CS
authors.lastname: Schindler
mesh_terms: D002384:Catalysis; D002712:Chlorides / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques; D005290:Ferric Compounds / Q000737:chemistry*; D006801:Humans; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D009285:Naphthoquinones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D002712:Chlorides; D005290:Ferric Compounds; D007659:Ketones; D009285:Naphthoquinones; D011714:Pyrans; C014638:beta-lapachone; C024555:ferric chloride; C415043:alpha-lapachone