More advanced oxidation of the cyclooctadienol shown, readily available in enantiomerically pure form from D-glucose, has given rise to a series of intermediates whose relative (and ultimately absolute) configuration was assigned on the basis of (1)H/(1)H coupling constant analysis. The selectivities that were deduced in this manner were drawn from the sequential application of CrO3 oxidation in tandem with Luche reduction, two-step NMO-promoted osmylations bracketed by acetonide formation, and wholesale deprotection. The stereoselectivities of these reactions were traced by (1)H NMR spectroscopy, and the stereochemical assignments were confirmed by the presence or absence of symmetry in the final cyclooctane polyols (four shown) generated in this investigation.
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http://dx.doi.org/10.1021/jo801443d | DOI Listing |
Molecules
October 2022
Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1-3, 119991 Moscow, Russia.
Reactions of oxirane ring opening provide a powerful tool for regio- and stereoselective synthesis of polyfunctional and heterocyclic compounds, widely used in organic chemistry and drug design. Cyclooctane, alongside other medium-sized rings, is of interest as a novel molecular platform for the construction of target-oriented leads. Additionally, cyclooctane derivatives are well known to be prone to transannular reactions, which makes them a promising object in the search for novel approaches to polycyclic structures.
View Article and Find Full Text PDFJ Org Chem
October 2008
Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
More advanced oxidation of the cyclooctadienol shown, readily available in enantiomerically pure form from D-glucose, has given rise to a series of intermediates whose relative (and ultimately absolute) configuration was assigned on the basis of (1)H/(1)H coupling constant analysis. The selectivities that were deduced in this manner were drawn from the sequential application of CrO3 oxidation in tandem with Luche reduction, two-step NMO-promoted osmylations bracketed by acetonide formation, and wholesale deprotection. The stereoselectivities of these reactions were traced by (1)H NMR spectroscopy, and the stereochemical assignments were confirmed by the presence or absence of symmetry in the final cyclooctane polyols (four shown) generated in this investigation.
View Article and Find Full Text PDFJ Org Chem
June 2006
Evans Chemical Laboratories, Ohio State University, Columbus, Ohio 43210, USA.
D-Arabinose and D-glucose are transformed into the identical vinyl furanoside, whose role is to serve as the precursor to enantiopure cyclooctadienone 6. The key steps of this relay involve a zirconocene-promoted ring contraction and [3,3] sigmatropic rearrangement of an enynol. Subsequently defined are convenient synthetic routes to several cyclooctane-1,2,3-triols, 1,2,3,4,5-pentaols, and structurally related glycomimetics.
View Article and Find Full Text PDFOrg Lett
February 2005
Evans Chemical Laboratories, Ohio State University, Columbus, OH 43210, USA.
[reaction: see text] A synthetic route to select cyclooctane-1,2,3-triols and 1,2,3,4,5-pentaols has been defined. The starting materials are d-glucose or d-arabinose, and the key steps consist of a zirconocene-promoted ring contraction, a [3,3] sigmatropic rearrangement, and more extended functionalization of the resulting cyclooctadienone.
View Article and Find Full Text PDFChem Commun (Camb)
December 2002
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, India.
Cyclooctatetraene (COT) derived bicyclo[4.2.1]nona-2,4,7-trien-9-one has been recognized as a cyclooctane carbasugar equivalent and elaborated to a range of cyclooctane polyols (cyclooctitols) through a flexible strategy with moderate regio- and stereo-control.
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