title: Efficient Synthesis of Functionalized [7]Helicenes.
abstract: [7]Helicenebisquinones can be made easily and in quantity by reacting the silyl enol ethers of a 9,10-dialkoxy-, or better a 9,10-disiloxy-, 3,6-diacetylphenanthrene, with p-benzoquinone. If an ethyl enol ether is used in place of the silyl enol ether, the transformation proceeds in much lower yield. The [7]helicenes are efficiently resolved into their enantiomers, and absolute configurations are assigned.
authors.affiliation: Department of Chemistry, Columbia University, New York, New York 10027.
authors.forename: Joseph M.
authors.initials: JM
authors.lastname: Fox
authors.forename: Naomi R.
authors.initials: NR
authors.lastname: Goldberg
authors.forename: Thomas J.
authors.initials: TJ
authors.lastname: Katz