title: Total Synthesis of Macrocarpines D and E via an Enolate-Driven Copper-Mediated Cross-Coupling Process: Replacement of Catalytic Palladium with Copper Iodide.
abstract: An enolate driven copper-mediated cross-coupling process enabled cheaper and greener access to the key pentacyclic intermediates required for the enantiospecific total synthesis of a number of C-19 methyl substituted sarpagine/macroline indole alkaloids. Replacement of palladium (60-68%) with copper iodide (82-89%) resulted in much higher yields. The formation of an unusual 7-membered cross-coupling product was completely inhibited by using TEMPO as a radical scavenger. Further functionalization led to the first enantiospecific total synthesis of macrocarpines D and E.
authors.affiliation: Department of Chemistry & Biochemistry, University of Wisconsin-Milwaukee , 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States.
authors.forename: M Toufiqur
authors.initials: MT
authors.lastname: Rahman
authors.affiliation: Center for Biomolecular Science and Engineering, Naval Research Laboratory , Code 6930, Washington, DC 20375, United States.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Deschamps
authors.forename: Gregory H
authors.initials: GH
authors.lastname: Imler
authors.affiliation: Department of Chemistry & Biochemistry, University of Wisconsin-Milwaukee , 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States.
authors.forename: Alan W
authors.initials: AW
authors.lastname: Schwabacher
authors.affiliation: Department of Chemistry & Biochemistry, University of Wisconsin-Milwaukee , 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States.
authors.forename: James M
authors.initials: JM
authors.lastname: Cook
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D007454:Iodides / Q000737:chemistry*; D008968:Molecular Conformation; D010165:Palladium / Q000737:chemistry*; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D007454:Iodides; D010165:Palladium; D003300:Copper; C073870:cuprous iodide; D010696:Phloroglucinol