title: Facile asymmetric synthesis of the core nuclei of xanthanolides, guaianolides, and eudesmanolides.
abstract: [reaction: see text] Bicyclic and tricyclic gamma-butyrolactones with 5,7-, 5,6,5-, 5,6,6-, or 5,7,5-fused ring systems, being found in xanthanolides, eudesmanolides, and guaianolides, were readily synthesized from methyl furan-2-carboxylic acid. Key steps were a copper(I)-catalyzed asymmetric cyclopropanation, Sakurai allylations, intramolecular ene reactions, and ring-closing metathesis reactions.
authors.affiliation: Institut für Organische Chemie der Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Nosse
authors.forename: Rakeshwar B
authors.initials: RB
authors.lastname: Chhor
authors.forename: Won Boo
authors.initials: WB
authors.lastname: Jeong
authors.forename: Claudius
authors.initials: C
authors.lastname: Böhm
authors.forename: Oliver
authors.initials: O
authors.lastname: Reiser