Stereostructure Reassignment and Absolute Configuration of Isoepitaondiol, a Meroditerpenoid from <i>Stypopodium flabelliforme</i>

Areche, Carlos; San-Martı́n, Aurelio; Rovirosa, Juana; Muñoz, Marcelo A.; Hernández-Barragán, Angelina; Bucio, María A.; Joseph‐Nathan, Pedro

doi:10.1021/np900553p

Cited by 37 publications

(33 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In this way, errors arising from assignments of configuration based on single NOE correlations may be avoided. Other common single stereocenter misassignments occur at ring junctions, as in the cases of manzacidin B, 74, 75 agelasine C 76, 77 and its epimer, 78 peyssonol A, 79, 80 isoepitaondiol, 81, 82 suberoretisteroid B 83, 84 and the green algal lanostane-type triterpenoid 85, 86 (Table 7), and are caused primarily by NMR spectral overlap. Assignment is also difficult for an isolated substituent on a macrocycle or extended chain, perhaps too far from the point of derivatization in a flexible system.…”

Section: Sources Of Natural Product Structural Misassignmentsmentioning

confidence: 99%

Survey of marine natural product structure revisions: A synergy of spectroscopy and chemical synthesis

Suyama

Gerwick

McPhail

2011

Bioorganic & Medicinal Chemistry

166

175

View full text Add to dashboard Cite

The structural assignment of new natural product molecules supports research in a multitude of disciplines that may lead to new therapeutic agents and or new understanding of disease biology. However, reports of numerous structural revisions, even of recently elucidated natural products, inspired the present survey of techniques used in structural misassignments and subsequent revisions in the context of constitutional or configurational errors. Given the comparatively recent development of marine natural products chemistry, coincident with the modern spectroscopy, it is of interest to consider the relative roles of spectroscopy and chemical synthesis in the structure elucidation and revision of those marine natural products which were initially misassigned. Thus, a tabulated review of all marine natural product structural revisions from 2005 to 2010 is organized according to structural motif revised. Misassignments of constitution are more frequent than perhaps anticipated by reliance on HMBC and other advanced NMR experiments, especially considering the full complement of all natural products. However, these techniques also feature prominently in structural revisions, specifically of marine natural products. Nevertheless, as is the case for revision of relative and absolute configuration, total synthesis is a proven partner for marine, as well as terrestrial, natural products structure elucidation. It also becomes apparent that considerable ‘detective work’ remains in structure elucidation, in spite of the spectacular advances in spectroscopic techniques.

show abstract

Section: Sources Of Natural Product Structural Misassignmentsmentioning

confidence: 99%

Survey of marine natural product structure revisions: A synergy of spectroscopy and chemical synthesis

Suyama

Gerwick

McPhail

2011

Bioorganic & Medicinal Chemistry

166

175

View full text Add to dashboard Cite

show abstract

“…[7] It is mostly used to assign absolute configurations of natural products, [8] pharmaceuticals, [9] and other chiral molecules including products of catalytic asymmetric reactions. [10] However,V CD spectroscopy is not only sensitive to the chirality of am olecule but also to conformational changes, [11] self-aggregation, [12] and intermolecular interactions with solvents.…”

mentioning

confidence: 99%

Stereochemical Communication within a Chiral Ion Pair Catalyst

et al. 2015

View full text Add to dashboard Cite

Ionic interactions are increasingly appreciated as a key, asymmetry-inducing factor in enantioselective catalytic transformations, including those involving Brønsted acid or base catalysis, phase-transfer catalysis, and related processes. However, a detailed understanding of these interactions is often lacking. Herein, we show how an enantiopure anion enforces a chiral conformation onto a catalytically relevant achiral cation. Specifically, we use vibrational circular dichroism (VCD) spectroscopy to monitor the transmission of stereochemical information from a chiral phosphate anion to a flexible manganese(III)-salen cation. We show that VCD can be used to study solvent effects and that the obtained chiroptical data directly and quantitatively correlate with the experimentally observed enantioselectivity in an asymmetric olefin epoxidation reaction.

show abstract

“…Moreover, the solid state structure of 158 revealed that the absolute configuration assignment based on the Flack parameter was considered non-conclusive, as evidenced by the use of Mosher esters. Thus, the absolute configuration assessment of 159 was determined by measurement of the VCD spectrum in combination with DFT B3LYP/DGDZVP calculations (259). The meroditerpenoid derivative 159 is a rather large molecule (C 31 H 44 O 5 ) with 36 non-hydrogen atoms and 270 electrons.…”

Section: Examplementioning

confidence: 99%