Matches in SemOpenAlex for { <https://semopenalex.org/work/W2022704080> ?p ?o ?g. }
Showing items 1 to 99 of
99
with 100 items per page.
- W2022704080 endingPage "372" @default.
- W2022704080 startingPage "363" @default.
- W2022704080 abstract "Chiral spirobinaphtopyrans 1–9 were synthesised using the acid catalyzed aldol condensation of 2-hydroxy-1-naphthaldehyde or 1-hydroxy-2-naphthaldehyde with the appropriate ketone and subsequent reaction of the isolated pyrylium salt with base. Separation or enrichment of enantiomers was accomplished by low-pressure liquid chromatography (LPLC) on triacetylcellulose, tribenzoylcellulose, or (+)-poly(triphenyl- methyl methacrylate) on SiO2. The barriers to thermal racemization were determined by dynamic 1H NMR measurements and by on-line or off-line measurements of the enriched enantiomers after LPLC. Barriers to thermal racemization for reversible cleavage of the Cspiro–O bond in 1–9 were found to be in the range 85–105 kJ/mol and are rationalized by steric and electronic effects. The ΔG≠ values decrease with decreasing length of the bridge or decreasing size of substituents in the 3 and 3′ positions. Therefore, ΔG≠ for 7>9>6, 3>2, and 4>1. Geometrical data from X-ray crystal structure analysis show that the mean value of the Cspiro–O bond length in the spirobibenzopyran 14 is shorter, i.e., the bond is stronger than that in the spirobinaphtho derivatives 4, 3, and 6. This bond-length shortening is explained by the weaker conjugation of the oxygen π-lone electron pair with the π-system of the benzene ring in 14 compared to the naphthalene moiety in 3, 4, and 6. Chirality 11:363–372, 1999. © 1999 Wiley-Liss, Inc." @default.
- W2022704080 created "2016-06-24" @default.
- W2022704080 creator A5012077562 @default.
- W2022704080 creator A5022849644 @default.
- W2022704080 creator A5032871465 @default.
- W2022704080 creator A5037164959 @default.
- W2022704080 creator A5047654790 @default.
- W2022704080 creator A5077155044 @default.
- W2022704080 creator A5082643639 @default.
- W2022704080 date "1999-01-01" @default.
- W2022704080 modified "2023-10-01" @default.
- W2022704080 title "Spirobinaphthopyrans: Synthesis, x-ray crystal structure, separation of enantiomers, and barriers to thermal racemization" @default.
- W2022704080 cites W1964493768 @default.
- W2022704080 cites W1966178449 @default.
- W2022704080 cites W1968331067 @default.
- W2022704080 cites W2003842893 @default.
- W2022704080 cites W2015826708 @default.
- W2022704080 cites W2036830910 @default.
- W2022704080 cites W2051078671 @default.
- W2022704080 cites W2053733231 @default.
- W2022704080 cites W2070479946 @default.
- W2022704080 cites W2071936780 @default.
- W2022704080 cites W2092282295 @default.
- W2022704080 cites W2125314372 @default.
- W2022704080 cites W2156102507 @default.
- W2022704080 cites W2160524890 @default.
- W2022704080 cites W2321115476 @default.
- W2022704080 cites W369111807 @default.
- W2022704080 cites W4300859885 @default.
- W2022704080 doi "https://doi.org/10.1002/(sici)1520-636x(1999)11:5/6<363::aid-chir3>3.0.co;2-f" @default.
- W2022704080 hasPublicationYear "1999" @default.
- W2022704080 type Work @default.
- W2022704080 sameAs 2022704080 @default.
- W2022704080 citedByCount "12" @default.
- W2022704080 countsByYear W20227040802012 @default.
- W2022704080 countsByYear W20227040802014 @default.
- W2022704080 countsByYear W20227040802015 @default.
- W2022704080 countsByYear W20227040802019 @default.
- W2022704080 countsByYear W20227040802021 @default.
- W2022704080 crossrefType "journal-article" @default.
- W2022704080 hasAuthorship W2022704080A5012077562 @default.
- W2022704080 hasAuthorship W2022704080A5022849644 @default.
- W2022704080 hasAuthorship W2022704080A5032871465 @default.
- W2022704080 hasAuthorship W2022704080A5037164959 @default.
- W2022704080 hasAuthorship W2022704080A5047654790 @default.
- W2022704080 hasAuthorship W2022704080A5077155044 @default.
- W2022704080 hasAuthorship W2022704080A5082643639 @default.
- W2022704080 hasBestOaLocation W20227040801 @default.
- W2022704080 hasConcept C115624301 @default.
- W2022704080 hasConcept C121332964 @default.
- W2022704080 hasConcept C124668440 @default.
- W2022704080 hasConcept C155647269 @default.
- W2022704080 hasConcept C155860418 @default.
- W2022704080 hasConcept C185592680 @default.
- W2022704080 hasConcept C201194858 @default.
- W2022704080 hasConcept C20621625 @default.
- W2022704080 hasConcept C486523 @default.
- W2022704080 hasConcept C52703039 @default.
- W2022704080 hasConcept C60002323 @default.
- W2022704080 hasConcept C62520636 @default.
- W2022704080 hasConcept C71240020 @default.
- W2022704080 hasConcept C7602139 @default.
- W2022704080 hasConcept C8010536 @default.
- W2022704080 hasConceptScore W2022704080C115624301 @default.
- W2022704080 hasConceptScore W2022704080C121332964 @default.
- W2022704080 hasConceptScore W2022704080C124668440 @default.
- W2022704080 hasConceptScore W2022704080C155647269 @default.
- W2022704080 hasConceptScore W2022704080C155860418 @default.
- W2022704080 hasConceptScore W2022704080C185592680 @default.
- W2022704080 hasConceptScore W2022704080C201194858 @default.
- W2022704080 hasConceptScore W2022704080C20621625 @default.
- W2022704080 hasConceptScore W2022704080C486523 @default.
- W2022704080 hasConceptScore W2022704080C52703039 @default.
- W2022704080 hasConceptScore W2022704080C60002323 @default.
- W2022704080 hasConceptScore W2022704080C62520636 @default.
- W2022704080 hasConceptScore W2022704080C71240020 @default.
- W2022704080 hasConceptScore W2022704080C7602139 @default.
- W2022704080 hasConceptScore W2022704080C8010536 @default.
- W2022704080 hasIssue "5-6" @default.
- W2022704080 hasLocation W20227040801 @default.
- W2022704080 hasOpenAccess W2022704080 @default.
- W2022704080 hasPrimaryLocation W20227040801 @default.
- W2022704080 hasRelatedWork W116012411 @default.
- W2022704080 hasRelatedWork W1482635079 @default.
- W2022704080 hasRelatedWork W2016118450 @default.
- W2022704080 hasRelatedWork W2147978589 @default.
- W2022704080 hasRelatedWork W2328533721 @default.
- W2022704080 hasRelatedWork W261939460 @default.
- W2022704080 hasRelatedWork W2951980110 @default.
- W2022704080 hasRelatedWork W2953172439 @default.
- W2022704080 hasRelatedWork W4206695463 @default.
- W2022704080 hasRelatedWork W4307705071 @default.
- W2022704080 hasVolume "11" @default.
- W2022704080 isParatext "false" @default.
- W2022704080 isRetracted "false" @default.
- W2022704080 magId "2022704080" @default.
- W2022704080 workType "article" @default.