The chemistry of fungi. Part LXVIII. The absolute configuration of (+)-sclerotiorin and of the azaphilones

Whalley, W. B.; Ferguson, George; Marsh, Wayne C.; Restivo, Roderic J.

doi:10.1039/p19760001366

Cited by 35 publications

(26 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, its CD spectrum was readily distinguishable from the two possible syn diastereomers (4 R ,8 R ,9 R and 4 R ,8 S ,9 S ) and more subtly distinguishable from the alternative anti (4 R ,8 R ,9 S )-diastereomer 66 (Figure 9). Like the simple azaphilone chromophore precursors 25−28 , the dipeptide azaphilone conjugates 45 and 46 , as well as the fully elaborated chromophore dipeptides 47 and 48 , the longest wavelength (395−415 nm) CD Cotton effect is positive for all four 4 R chlorofusin diastereomers as well as the natural product firmly establishing the absolute configuration assignment 44-46…”

Section: Resultsmentioning

confidence: 80%

Total Synthesis of Chlorofusin, Its Seven Chromophore Diastereomers, and Key Partial Structures

2008

View full text Add to dashboard Cite

Chlorofusin is a recently isolated, naturally occurring inhibitor of p53−MDM2 complex formation whose structure is composed of a densely functionalized azaphilone-derived chromophore linked through the terminal amine of ornithine to a nine residue cyclic peptide. Herein we report the full details of the total synthesis of chlorofusin, resulting in the assignment of the absolute stereochemistry and reassignment of the relative stereochemistry of the complex chromophore. Condensation of each enantiomer of an azaphilone chromophore precursor with the Nδ-amine of a protected ornithinethreonine dipeptide, followed by a one-step oxidation/spirocyclization of the most reactive olefin provided all eight diastereomers of the fully elaborated chromophore−dipeptide conjugate. Comparison of the spectroscopic properties for these eight compounds and those of simpler models with that reported for the natural product allowed the full assignment of the (4R,8S,9R)-stereochemistry of the chlorofusin chromophore. The natural, but stereochemically reassigned, diastereomer of the dipeptide conjugate was incorporated in a convergent total synthesis of chlorofusin confirming the stereochemical reassignment and establishing its absolute stereochemistry. Similarly and enlisting the late stage convergent point in the total synthesis, the remaining seven diastereomers of the chromophore−dipeptide conjugates were individually incorporated into the 9-residue cyclic peptide of chlorofusin (4 steps each) providing all seven remaining possible chromophore diastereomers of the natural product.

show abstract

Section: Resultsmentioning

confidence: 80%

Total Synthesis of Chlorofusin, Its Seven Chromophore Diastereomers, and Key Partial Structures

2008

View full text Add to dashboard Cite

show abstract

“…Whalley et al have shown that the sign of the specific rotation of azaphilones is apparently controlled by the absolute configuration at C-7. 16 Steyn and Vleggaar established the absolute stereochemistry of azaphilones from the definition of the absolute configuration at C-7 of (þ)-sclerotiorin in the CD spectra. In addition, they revealed that the Cotton curve remained unaffected by the functional groups at C-8.…”

Section: Resultsmentioning

confidence: 99%

Chaetomugilins I–O, new potent cytotoxic metabolites from a marine-fish-derived Chaetomium species. Stereochemistry and biological activities

et al. 2009

View full text Add to dashboard Cite

“…From the literature [7,14,15], it is known that the absolute configuration of the stereocenter at C-7 of compounds 1 and 2 can be deduced from the CD effect at around 390 nm. The stereocenter at C-13, however, has no impact on the CD and is thus out of the scope of such measurements.…”

Section: Resultsmentioning

confidence: 99%

Helicusin E, Isochromophilone X and Isochromophilone XI: New Chloroazaphilones Produced by the Fungus Bartalinia robillardoides Strain LF550

et al. 2013

View full text Add to dashboard Cite

Microbial studies of the Mediterranean sponge Tethya aurantium led to the isolation of the fungus Bartalinia robillardoides strain LF550. The strain produced a number of secondary metabolites belonging to the chloroazaphilones. This is the first report on the isolation of chloroazaphilones of a fungal strain belonging to the genus Bartalinia. Besides some known compounds (helicusin A (1) and deacetylsclerotiorin (2)), three new chloroazaphilones (helicusin E (3); isochromophilone X (4) and isochromophilone XI (5)) and one new pentaketide (bartanolide (6)) were isolated. The structure elucidations were based on spectroscopic analyses. All isolated compounds revealed different biological activity spectra against a test panel of four bacteria: three fungi; two tumor cell lines and two enzymes.

show abstract

The chemistry of fungi. Part LXVIII. The absolute configuration of (+)-sclerotiorin and of the azaphilones

Cited by 35 publications

References 0 publications

Total Synthesis of Chlorofusin, Its Seven Chromophore Diastereomers, and Key Partial Structures

Total Synthesis of Chlorofusin, Its Seven Chromophore Diastereomers, and Key Partial Structures

Chaetomugilins I–O, new potent cytotoxic metabolites from a marine-fish-derived Chaetomium species. Stereochemistry and biological activities

Helicusin E, Isochromophilone X and Isochromophilone XI: New Chloroazaphilones Produced by the Fungus Bartalinia robillardoides Strain LF550

Contact Info

Product

Resources

About