title: A triple diene-transmissive Diels-Alder strategy to build the quassinoid framework.
abstract: [chemical reaction: see text]. An advanced intermediate to the highly oxygenated triterpene quassinoids was prepared in 14 steps from tetrahydrofuran. The key steps are three diene-transmissive Diels-Alder cycloadditions. Several features of this synthesis are noteworthy, including a successful Mitsunobu reaction on an allenylic alcohol, a rare [4 + 2] cycloaddition involving an enethiol ether dienophile, and complete control over all 10 chiral centers created.
authors.affiliation: Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, Canada J1K 2R1.
authors.forename: Amélie
authors.initials: A
authors.lastname: Dion
authors.forename: Pascal
authors.initials: P
authors.lastname: Dubé
authors.forename: Claude
authors.initials: C
authors.lastname: Spino
mesh_terms: D003500:Cyclization; D005663:Furans / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D036702:Quassins / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D005663:Furans; D036702:Quassins