title: Highly efficient and tunable synthesis of dioxabicyclo[4.2.1] ketals and tetrahydropyrans via gold-catalyzed cycloisomerization of 2-alkynyl-1,5-diols.
abstract: A highly efficient gold(I) chloride catalyzed cycloisomerization of 2-alkynyl-1,5-diol (1) to dioxabicyclo[4.2.1] ketal (2) and its further transformation to tetrahydropyran (3) are reported. The diol is readily obtained by the reduction of 2-alkynyl-substituted glutarates, isolated from the Michael addition of allenoates to methyl acrylate. These reactions proceeded smoothly under very mild conditions. A plausible mechanism for the formation of the said tetrahydropyran from the corresponding ketal is proposed.
authors.affiliation: Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA. leping.liu@louisville.edu
authors.forename: Le-Ping
authors.initials: LP
authors.lastname: Liu
authors.forename: Gerald B
authors.initials: GB
authors.lastname: Hammond