title: Enantioselective Total Synthesis of Terreumols A and C from the Mushroom Tricholoma terreum.
abstract: The cytotoxic meroterpenoids terreumol A and C from the grey knight mushroom Tricholoma terreum were synthesized for the first time. The key step of the enantioselective total synthesis of terreumol C is a ring-closing metathesis to form a trisubstituted Z double bond embedded in the 10-membered ring of the [8.4.0] bicycle. Interestingly, the presence of a free hydroxy group in the metathesis precursor prevents cyclization and favors cross metathesis. (-)-Terreumol C was converted into (-)-terreumol A by diastereoselective epoxidation. Starting from 2-bromo-3,5-dimethoxybenzaldehyde, 14 steps with an overall yield of 23 % are needed for the synthesis of (-)-terreumol A. X-ray analysis of the benzoquinone analogue of terreumol A provides independent proof of the absolute configuration.
authors.affiliation: Institute of Organic Chemistry, Technical University Braunschweig, Hagenring 30, 38106, Braunschweig, Germany.
authors.forename: Alex
authors.initials: A
authors.lastname: Frichert
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Technical University Braunschweig, Hagenring 30, 38106, Braunschweig, Germany.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Jones
authors.affiliation: Institute of Organic Chemistry, Technical University Braunschweig, Hagenring 30, 38106, Braunschweig, Germany. th.lindel@tu-braunschweig.de.
authors.forename: Thomas
authors.identifier: http://orcid.org/0000-0003-1472-490X
authors.initials: T
authors.lastname: Lindel
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D013237:Stereoisomerism; D013729:Terpenes / Q000138:chemical synthesis* / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D013729:Terpenes; C584225:terreumol A; C584226:terreumol C
keywords: medium-sized rings; meroterpenoids; natural products; ring-closing metathesis; total synthesis