A Novel Synthesis of the Fluorene Skeleton

Corey, E. J.; Azimioara, Mihai; Fischer, Axel

doi:10.1016/s0040-4039(97)01534-7

Cited by 25 publications

(40 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(In the cases investigated, this applies also to (P)-Ti-BINOLates.) [399] Discussion regarding a stereochemical course for this reaction that leads to the observed result is summarized in Scheme 28. Despite the overwhelming number of known examples, no generally accepted common reaction mechanism has yet been elucidated.…”

Section: Reviewsmentioning

confidence: 99%

“…2001, 40, 92 ± 138 125 Scheme 28. Models for the stereochemical course of cycloadditions and ene reactions of enoyloxazolidinones RCHCH-CO 6. a) Configuration of the product formed with (R,R)-titanium-TADDOLate (see also (P)-titanium-BINOLate Lewis acids [399] ). b) Preferred conformation, as observed in numerous X-ray structures, [400] for 3-acyloxazolidinones with synperiplanar (sp)/antiperiplanar (ap) conformations of COÀN and COÀCH bonds, respectively, as well as sp/sp arrangements in metal complexes [401,402] and destabilized ap/sp geometry due to 1,5-repulsion (Newman or A 1,3 strain [403] ).…”

Section: Reviewsmentioning

confidence: 99%

See 1 more Smart Citation

TADDOLs, Their Derivatives, and TADDOL Analogues: Versatile Chiral Auxiliaries

Seebàch

Beck

Heckel

2001

Angew. Chem. Int. Ed.

535

View full text Add to dashboard Cite

Section: Reviewsmentioning

confidence: 99%

Section: Reviewsmentioning

confidence: 99%

TADDOLs, Their Derivatives, and TADDOL Analogues: Versatile Chiral Auxiliaries

Seebàch

Beck

Heckel

2001

Angew. Chem. Int. Ed.

535

View full text Add to dashboard Cite

“…Since it is (9), [42] the hope was that 10 should be produced analogously, provided that the substrate mixture contained at least some 33 or its pseudo-ortho isomer. On work-up, the PARYLENE C had vanished completely, but unfortunately again no defined products could be isolated.…”

mentioning

confidence: 99%

MP2 and DFT Calculations on Circulenes and an Attempt to Prepare the Second Lowest Benzolog, [4]Circulene

Christoph

Grunenberg

Hopf

et al. 2008

Chemistry A European J

View full text Add to dashboard Cite

MP2 and DFT calculations have been carried out for [n]circulenes for n=3 to 20 in order to predict the strain energy and topology of these cyclically condensed aromatic systems. To synthesise [4]circulene (2), 1,5,7,8-tetrakis(bromomethyl)biphenylene (14) was prepared from the corresponding tetramethyl derivative (8) and subjected to various dehalogenation reactions; all attempts to obtain [2.2]biphenylenophane (7) as a precursor for 2 by this route failed. Treatment of 14 with sodium sulfide furnished the thiaphanes 16 and 17, thermal and photochemical desulfurization of which also failed to provide 7. In a second approach [2.2]paracyclophane was converted to the pseudo-geminal dithiol 23, which was subsequently bridged to the thiaphanes 22 and 24. On flash vacuum pyrolysis at 800 degrees C these were converted exclusively into phenanthrene (30). An approach to dehydrochlorinate the commercial product PARYLENE C to the tetrahydro[4]circulene 7 led only to polymerisation. The X-ray structures of the intermediates 8, 14, 17, 23, 24, 26, and 35 are reported.

show abstract

“…Tatsache ist, dass alle nucleophilen Additionen ± einschlie˚lich der EnReaktion ± an die Doppelbindung dieser a,b-unges‰ttigten Carbonylverbindungen (unter Erhaltung der trans-Konfiguration) mit (R,R)-Ti-TADDOLaten von der (Re)-Seite am trigonalen Zentrum neben der Carbonylgruppe erfolgen (wo untersucht, gilt das auch wieder f¸r (P)-Ti-BINOLate)! [399] In Schema 28 sind die Diskussionen¸ber den zu diesem Ergebnis f¸hrenden stereochemischen Verlauf der Reaktion zusammengefasst. Trotz der¸berw‰ltigenden Zahl von Bei-128 Angew.…”

Section: Mechanistische Erˆrterungen Der Enantioselektiven Lewis-s‰urunclassified

“…Modelle zum stereochemischen Verlauf der Cycloadditionen und En-Reaktionen von Enoyloxazolidinonen RCHCHÀCO X . a) Konfiguration der mit (R,R)-Ti-TADDOLaten gebildeten Produkte (siehe auch (P)-Ti-BINOLat-Lewis-S‰uren [399] ). b) In zahlreichen Strukturen im Kristall [400] gefundene Vorzugskonformation von 3-Acyloxazolidinonen mit synperiplanarer/antiperiplanarer (sp/ap) Konformation von CO-N-bzw.…”

Section: Mechanistische Erˆrterungen Der Enantioselektiven Lewis-s‰urunclassified

TADDOLe, ihre Derivate und Analoga – vielseitige chirale Hilfsstoffe

2001

View full text Add to dashboard Cite

Das Bild der Erde wird von der NASA zur Verfügung gestellt (rsd.gsfc.nasa.gov/rsd) und der linke obere Bildausschnitt wurde mit dem Hubble-Teleskop aufgenommen (oposite.stsci.edu/pubinfo/PR/2000/20/pr-photos.html). Das Bild der Erde wurde von der NASA zur Verfügung gestellt (rsd.gsfc.nasa.gov/rsd), und der linke obere Bildausschnitt wurde mit dem Hubble-Teleskop aufgenommen (oposite.stsci.edu/pubinfo/PR/2000/20/pr-photos.html). Hintergrundinformationen zu diesem Beitrag sind im WWW unter http://www.angewandte.de zu finden oder kˆnnen beim Autor angefordert werden. Sie enthalten eine Liste der 297 derzeit bekannten TADDOL-Derivate [467] mit Hinweisen auf vorhandene Rˆntgenstruk-turdaten sowie auf Literaturstellen zur Herstellung, Verwendung und Diskussion dieser Derivate. Diese Liste enth‰lt auch weitere 73 Literaturzitate.

show abstract

A Novel Synthesis of the Fluorene Skeleton

Cited by 25 publications

References 5 publications

TADDOLs, Their Derivatives, and TADDOL Analogues: Versatile Chiral Auxiliaries

TADDOLs, Their Derivatives, and TADDOL Analogues: Versatile Chiral Auxiliaries

MP2 and DFT Calculations on Circulenes and an Attempt to Prepare the Second Lowest Benzolog, [4]Circulene

TADDOLe, ihre Derivate und Analoga – vielseitige chirale Hilfsstoffe

Contact Info

Product

Resources

About