title: Enantioselective Synthesis of the Tricyclic Core of FR901483 Featuring a Rh-Catalyzed [2+2+2] Cycloaddition.
abstract: An efficient approach to the tricyclic framework of FR901483 is described. The sequence features a [3, 3]-sigmatropic rearrangement of a cyanate into an isocyanate, followed by its subsequent asymmetric rhodium-catalyzed [2+2+2] cycloaddition with a terminal alkyne for the synthesis of the indolizidine core. Theaza-tricyclic core is completed using an intramolecular benzoin reaction to close the last ring of the natural product. Through a model study of the key cycloaddition, we evaluated the impact of different substituents on the tether of the alkenyl isocyanate.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, CO 80523.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Perreault
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, CO 80523.
authors.forename: Tomislav
authors.initials: T
authors.lastname: Rovis