The first enantioselective total synthesis of epiplakinic acid F (1) was achieved through a pivotal step involving a radical-mediated asymmetric peroxidation of vinylcyclopropanes with molecular oxygen to construct highly substituted 1,2-dioxolanes. Subsequent conversions of the chiral 1,2-dioxolanes led to total synthesis of epiplakinic acid F (1) and the confirmation of its absolute configuration. The enantiomer of epiplakinic acid F methyl ester (2) was also prepared.
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Org Lett
March 2017
Department of Molecular Medicine, Beckman Research Institute, City of Hope , 1500 East Duarte Road, Duarte, California 91010, United States.
Plakortinic acids A (2) and B (3), two polyketide endoperoxides with a bicyclo[4.2.0]octene unit, were isolated as minor constituents from the sponge-sponge symbiotic association Plakortis halichondrioides-Xestospongia deweerdtae, along with known epiplakinic acid F (1).
View Article and Find Full Text PDFOrg Biomol Chem
June 2014
Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, The Chinese Academy of Sciences, 345 Ling Ling Road, Shanghai 200032, China.
The first enantioselective total synthesis of epiplakinic acid F (1) was achieved through a pivotal step involving a radical-mediated asymmetric peroxidation of vinylcyclopropanes with molecular oxygen to construct highly substituted 1,2-dioxolanes. Subsequent conversions of the chiral 1,2-dioxolanes led to total synthesis of epiplakinic acid F (1) and the confirmation of its absolute configuration. The enantiomer of epiplakinic acid F methyl ester (2) was also prepared.
View Article and Find Full Text PDFJ Nat Prod
October 2010
Department of Chemistry, University of Puerto Rico, P.O. Box 23346, UPR Station, San Juan, Puerto Rico 00931-3346, USA.
Two new five-membered-ring polyketide endoperoxides, epiplakinic acid F methyl ester (1) and epiplakinidioic acid (3), and a peroxide-lactone, plakortolide J (2), were isolated from the Puerto Rican sponge Plakortis halichondrioides, along with two previously reported cyclic peroxides, 4 and 5. The structures of the new metabolites were determined by spectroscopic and chemical analyses. The absolute stereostructures of 1, 2, and 5 were determined by degradation reactions followed by application of Kishi's method for the assignment of absolute configuration of alcohols.
View Article and Find Full Text PDFJ Nat Prod
September 2002
Scripps Institution of Oceanography, University of California at San Diego, La Jolla 92093-0212, USA.
Four beta-carbolines, plakortamines A-D, two cyclic peroxides, epiplakinic acids G and H, and two related gamma-lactones, (2S,4R)- and (2R,4R)-2,4-dimethyl-4-hydroxy-16-phenylhexadecanoic acid 1,4-lactones, were isolated from the deep-water sponge Plakortis nigra from Palau. The structures of the eight new metabolites were elucidated by interpretation of spectroscopic data. Most of the metabolites inhibited the HCT-116 human colon tumor cell line.
View Article and Find Full Text PDFJ Nat Prod
February 2001
Division of Biomedical Marine Research, Harbor Branch Oceanographic Institution, Inc., 5600 US 1 North, Ft. Pierce, Florida 34946, USA.
Two new five-membered-ring peroxide acids, plakinic acid F (3) and epiplakinic acid F (4), and a new peroxide-lactone, plakortolide F (5), were isolated from a sponge of the genus Plakinastrella collected from Felicite Island, Seychelles. The structures were elucidated through spectral analysis. The free acids 3 and 4 exhibit moderate antifungal activity against Candida albicans with minimum inhibitory concentrations of 25 micrograms/mL (SDB) and 3.
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