title: A Concise Synthesis ofR-(-)-Cicutoxin, a Natural 17-Carbon Polyenyne.
abstract: A concise synthesis of the natural polyenyneR-(-)-cicutoxin (1) is described. After several trials, the successful synthesis commenced with three key fragments,R-(-)-1-hexyn-3-ol (8), 1,4-diiodo-1,3-butadiene (9), and the THP protected 4,6-heptadiyn-1-ol (6). Sonogashira coupling of compound9with acetylenes6and8gave the 17-carbon frame, which upon regio-selective reduction of a triple bond with red Al and removal of the THP protecting group afforded the natural product in four linear steps. The triply convergent synthesis gaveR-(-)-cicutoxin in 18% overall yield.
authors.affiliation: Department of Chemistry & Biochemistry, Miami University, Oxford, OH 45056.
authors.forename: Benjamin W
authors.initials: BW
authors.lastname: Gung
authors.forename: Ann O
authors.initials: AO
authors.lastname: Omollo
keywords: Total synthesis; antileukemic; cicutoxin; natural product