Asymmetric Total Synthesis of Fusarentin 6-Methyl Ether and Its Biomimetic Transformation into Fusarentin 6,7-Dimethyl Ether, 7-O-Demethylmonocerin, and (+)-Monocerin

Abstract

A concise asymmetric total synthesis of a fusarentin ether (1) with sequential biomimetic transformation to its analogues fusarentin 6,7-dimethyl ether (2), 7-O-demethylmonocerin (3), and (+)-monocerin (4) has been accomplished. The cis-fused furobenzopyranones of 7-O-demethylmonocerin (3) and (+)-monocerin (4) were efficiently constructed via an intramolecular nucleophilic trapping of a quinonemethide intermediate, which was obtained by benzylic oxidation of fusarentin 6-methyl ether (1) using hypervalent iodine reagent.

Enantioselective Total Synthesis of (+)-Monocerin, a Dihydroisocoumarin Derivative with Potent Antimalarial Properties

“…The 1 H NMR and 13 C NMR spectra of our synthetic bicyclic ether 19 showed excellent agreement with the reported derivative. 18 Furthermore, NOESY correlation of cis-hydrogens in compound 17 supported stereochemistry of 17 and 19 (see the Supporting Information for details). Oxidation of the isochroman ring was carried out with CrO 3 and pyridine in CH 2 Cl 2 at 0 to 23 °C for 36 h to provide lactone derivative 20 in 40% yield (60% brsm).…”

New α-glucosidase inhibitors from a marine sponge-derived fungus, Aspergillus sp. OUCMDZ-1583

“…In conclusion, eighteen new compounds (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) were isolated from the marine sponge-derived Aspergillus sp. strain OUCMDZ-1583.…”

“…The EtOAc extract of the fermentation broth showed a-glucosidase inhibition with an IC 50 value of 0.97 mg mL À1 , while the IC 50 value of acarbose (the positive control) was 0.61 mg mL À1 . Chemical examination of the fermentation broth resulted in the isolation and identication of eighteen new compounds that we named aspergones A-Q (1-17) and 6-O-demethylmonocerin (18), as well as ve known compounds: epoxyquinol (19), 10 7-O-demethylmonocerin (20), 11 (+)-monocerin (21), 11,12 fusarentin 6methyl ether (22), 11 and 6,7-O-dimethyl-4R-hydroxy-10epifusarentin ( 23) 13 (Table S1, ESI †).…”

Setosphaerine A: A New Chlorinated Polyketide Isolated From the Entomogenous Fungus Setosphaeria rostrata

“…Compounds 2 to 4 were identified as penicipyrans D, 2,11 7- O -demethymonocerin, 3,12 and monocerin, 4,13 by comparison of their NMR data with those reported in the literature.…”