34094-63-8Relevant academic research and scientific papers
Hydroxylic additives enhance yield and scalability of silicon-directed Nazarov reaction
Joy, Shaon,Nakanishi, Waka,West
, p. 5573 - 5576 (2013/09/23)
As a result of difficulties in scaling up silicon-directed Nazarov cyclization for use in the synthesis of taxane natural products, the effect of additives was examined. Hydroxylic additives were found to convey a consistent beneficial effect on the rate, overall yield, and scalability of these reactions. Optimal conditions (1.5 equiv methanol or water with substoichiometric FeCl3), were successfully applied to a range of β-silyl dienone substrates, including several complex polycyclic examples, as well as simpler dienones previously shown to be low-yielding or completely unreactive under the conventional conditions.
INTRAMOLECULAR ACYLATION OF α-SULFINYL CARBANION: A NEW GENERAL ROUTE TO 5-SUBSTITUTED Δ2-CYCLOPENTENONES
Pohmakotr, Manat,Phinyocheep, Pranee
, p. 2249 - 2252 (2007/10/02)
A general method for the preparation of 5-substituted Δ2-cyclopentenones via the intramolecular acylation of α-sulfinyl carbanions has been demonstrated.
Silicon-Directed Nazarov Reactions II. Preparation and Cyclization of β-Silyl-substituted Divinyl Ketones
Jones, Todd K.,Denmark, Scott E.
, p. 2377 - 2396 (2007/10/02)
Two general methods for the preparation of β-silyl-substituted divinyl ketones have been developed starting from either α,β-unsaturated aldehydes or simple ketones.Anhydrous FeCl3 induces the cyclization to cyclopentenones under mild conditions and in good yields with predictable and complete control over the position of the double bond in the five-membered ring.The observed effects of substituents on rate can be explained by a rate-determining cationic electrocyclization.Silyl substitution has been shown to retard the reaction.
Specificities of the α-Alkynone Cyclization
Karpf, Martin,Huguet, Joan,Dreiding, Andre S.
, p. 13 - 25 (2007/10/02)
Die Regio- und Stereospezifitaeten der α-Alkinon-Cyclisierung, einer thermischen Umwandlung von Alkinyl-alkyl-ketonen, welche in β'-Stellung mindestens ein H-Atom tragen, zu 2-Cyclopentenonen wurden untersucht.Cyclisierung zum hoeher substituierten C(β')-Atom ist dabei bevorzugt, vorausgesetzt, dass die zur Insertion zur Verfuegung stehende C(β'),H-Bindung zur Propioloylseitenkette eine moeglichst synplanare Anordnung einnehmen kann.In Cyclisierungen zu β'-Methylen-C-Atomen, welche diastereotope H-Atome tragen, wird daher eines der moeglichen epimeren Produkte bevorzugt oder ausschliesslich gebildet.Die mechanistischen Konsequenzen der gefundenen Specifitaeten werden diskutiert.
