New Concise and Efficient Synthesis of Rubrolides C and E <i>via</i> Intramolecular <i>Wittig</i> Reaction

Tale, Nilesh P.; Shelke, Amol V.; Tiwari, Girdharilal B.; Thorat, Prerana B.; Karade, Nandkishor N.

doi:10.1002/hlca.201100351

Cited by 20 publications

(11 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The synthesis and experimental NMR properties of 5‐phenethyloxazole ( 1 ) and 4‐iodo‐5‐phenethyloxazole ( 2 ) were reported by Vedejs et al . Breitfussin A ( 3 ) and Breitfussin B ( 4 ) are naturally occurring organic compounds, and their extractions and NMR spectra were reported recently by Hansen et al ., Rubrolide E ( 5 ) and Rubrolide I ( 6 ) are also naturally occurring anti‐inflammatory organic compounds, and their NMR spectra were reported by Tale et al . and Ortega et al ., respectively.…”

Section: Introductionmentioning

confidence: 83%

Four‐component relativistic chemical shift calculations of halogenated organic compounds

Demissie

Repiský

Komorovský

et al. 2013

J of Physical Organic Chem

View full text Add to dashboard Cite

The calculation of nuclear magnetic resonance (NMR) properties of organic compounds with heavy elements has been a computational challenge due to the importance of relativistic effects and the cost of relativistic calculations capable of capturing these effects. The heavy-atom effect on the chemical shift of light atoms also challenges the interpretation of NMR spectra of organic compounds, since relativistic effects can affect the predicted values of protons bonded to heavy atoms by as much as 20 ppm. Here, we investigate the chemical shifts of six organic compounds with/without halogen atoms using non-relativistic and state-of-the-art four-component relativistic methods, comparing the results to available experimental data. Our study confirms the importance of relativistic effects in modeling NMR properties of organic compounds involving heavy atoms and shows that these effects cannot be properly described by non-relativistic methods. We also demonstrate that relativistic four-component calculations of NMR chemical shifts now have reached a level of maturity that allows these methods to be used routinely in theoretical studies of NMR properties of large organic compounds containing heavy elements. The accuracy of these calculations is high enough to allow them to be used in assisting in the structural characterization of natural compounds. Comparison of the GGA functionals used in the four-component relativistic density functional theory calculations shows that the PBE functional seems to be well suited for such studies.

show abstract

Section: Introductionmentioning

confidence: 83%

Four‐component relativistic chemical shift calculations of halogenated organic compounds

Demissie

Repiský

Komorovský

et al. 2013

J of Physical Organic Chem

View full text Add to dashboard Cite

show abstract

“…Shortly thereafter, we described a short synthesis of rubrolides C and E (Figure , 5 and 6 ) using a new strategy based on Suzuki cross‐coupling and furanolate chemistry . Subsequent syntheses of rubrolide E have employed Meerwein coupling, a Heck‐type reaction, ring‐closing metathesis, and an intramolecular Wittig reaction, which also enabled the synthesis of rubrolide C . The first α‐chloro‐substituted congener (rubrolide M, Figure , 7 ) was synthesized by Bellina et al by application of a site‐selective Suzuki cross‐coupling .…”

Section: Introductionmentioning

confidence: 99%

Late‐Stage Bromination Enables the Synthesis of Rubrolides B, I, K, and O

et al. 2016

View full text Add to dashboard Cite

A concise and efficient synthesis of the marine natural products rubrolides B, I, K, and O was accomplished in 3–4 steps from commercially available 3,4‐dichloro‐2(5H)‐furanone. Key steps include: (i) a site‐selective Suzuki cross‐coupling, (ii) a vinylogous aldol condensation, and (iii) a late‐stage bromination. The latter reaction allowed functionalization of the aromatic rings in a highly regioselective fashion, enabling rapid access to the target rubrolides from common precursors.

show abstract

“…950 New efficient syntheses of rubrolides C and E have been reported. 951 Potently cytotoxic macrolides mandelalide A-D 1193-1196 were isolated from Lissoclinum sp. (Algoa Bay, South Africa); relative congurations were assigned by extensive J-based and rOe analysis and absolute conguration was assigned to 1193 by a combination of sugar analysis (GC-MS) and rOe data.…”

mentioning

confidence: 99%

Marine natural products

et al. 2014

View full text Add to dashboard Cite

This review covers the literature published in 2012 for marine natural products, with 1035 citations (673 for the period January to December 2012) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1241 for 2012), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

show abstract

New Concise and Efficient Synthesis of Rubrolides C and E via Intramolecular Wittig Reaction

Cited by 20 publications

References 17 publications

Four‐component relativistic chemical shift calculations of halogenated organic compounds

Four‐component relativistic chemical shift calculations of halogenated organic compounds

Late‐Stage Bromination Enables the Synthesis of Rubrolides B, I, K, and O

Marine natural products

Contact Info

Product

Resources

About