title: Optically active calixarenes conduced by methylene substitution.
abstract: The first method for the synthesis of optically active calix[4]arenes that are chiral as a result of substitution on the methylene bridges is described. The key step in the synthesis involves the reaction of a biscarbene complex with a diyne, which generates two of the benzene rings and the macrocyclic ring of the calix in a single transformation. The utility of this triple annulation process is demonstrated in the synthesis of di- and tetramethoxycalix[4]arenes. The flexibility of this synthetic approach is demonstrated by the synthesis of two diastereomers of the tetramethoxycalix[4]arenes in which each is synthesized in a stereoselective fashion by proper control of the absolute configurations of the methoxy groups in the biscarbene complex and in the diyne.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Vijay
authors.initials: V
authors.lastname: Gopalsamuthiram
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Predeus
authors.forename: Rui H
authors.initials: RH
authors.lastname: Huang
authors.forename: William D
authors.initials: WD
authors.lastname: Wulff