56975-51-0Relevant academic research and scientific papers
SYNTHESIS OF 2-METHYL-1-CYCLOPENTADECANONE FROM CYCLODODECANONE
Zakharin, L. I.,Pryanishnikov, A. P.,Guseva, V. V.
, p. 80 - 83 (2007/10/02)
1-(3-Buten-1-ynyl)-1-cyclododecanol was obtained from cyclododecanone and 1-buten-3-yne, and its cyclization to 15-methylbicyclopentadec-1(12)-en-13-one was studied.The latter was used for the synthesis of 2-methyl-1-cyclopentadecanone, 2-methyl-4-cyclopentadecen-1-one, and 15-methylbicyclopentadecan-13-one.
Three-Carbon Annelations. Regiocontrolled Reactivity of Trimethylsilyl- and Ethoxyethyl-Protected Cyanohydrins. Versatile Homoenolate and Acyl Anion Equivalents
Jacobson, Richard M.,Lahm, George P.,Clader, John W.
, p. 395 - 405 (2007/10/02)
The trimethylsilyl- (2) and ethoxyethyl- (4) protected cyanohydrins of α,β-unsaturated aldehydes are utilized as three-carbon annelation reagents.Metalated reagent 2 displays exclusive α reactivity with aldehydes and ketones at -78 deg C.Metalated reagent 4 displays exclusive α reactivity at -78 deg C and exclusive γ reactivity at 0 deg C.Reagent 4 thus allows for complete regiocontrol in its addition to aldehydes and ketones which permits selective addition of either a homoenolate or an acyl anion equivalent.Metalation of the α product 11 at -78 deg C with subsequent warming to 0 deg C produces exclusively the γ product, confirming the reversible nature of the addition to the carbonyl.The derived α '-trimethylsiloxy enones 17 (R3=Me3Si), α '-hydroxy enones 17 (R3=H), α '-acetoxyenones 17 (R3=Ac), and γ-lactones 10 are useful cyclopentenone precursors.Treatment of 17 with p-TsOH in toluene at reflux produces cyclopentenones.The reaction proceeds via the postulated intermediacy of a pentadienyl cation 15 which undergoes in situ electrocyclic ring closure.
Silanes in Organic Synthesis. 8. Preparation of Vinylsilanes from Ketones and Their Regiospecific Cyclopentenone Annulation
Paquette, Leo A.,Fristad, William E.,Dime, David S.,Bailey, Thomas R.
, p. 3017 - 3028 (2007/10/02)
A general method is described for the formation of vinylsilanes from ketones.Thus, conversion to the benzene- or p-toluenesulfonylhydrazone and sequential treatment with n-butyllithium and chlorotrimethylsilane in anhydrous tetramethylethylenediamine proceeds regiospecifically to afford the less substituted vinylsilane (in unsymmetrical cases).Friedel-Crafts acylation with acryloyl chlorides and aluminium chloride and subsequent Nazarov cyclization with Lewis acid catalysis results in cyclopentenone annulation.Numerous examples that reveal the scope of this processare described.Due to accompanying polymerization, annulation with acryloyl chloride itself is least efficient.This complication can, however, be averted through use of β-chloropropionyl chloride and dehydrochlorination with 1,5-diazabicycloundec-5-ene prior to ring closure.
Vinylsilane mediated regiospecific cyclopentenone annulation of ketones
Fristad, William E.,Dime, David S.,Thomas R, Bailey,Leo A, Paquette
, p. 1999 - 2002 (2007/10/10)
The development of a new cyclopentenone annulation sequence of general scope which involves Friedel-Crafts acylation of a vinylsilane with an α,β-unsaturated acid chloride followed by Nazarov cyclization is reported.
