13404-66-5Relevant academic research and scientific papers
Enantioselective Intermolecular [2+2] Photocycloaddition Reaction of Cyclic Enones and Its Application in a Synthesis of (-)-Grandisol
Poplata, Saner,Bach, Thorsten
supporting information, p. 3228 - 3231 (2018/03/13)
The intermolecular [2+2] photocycloaddition of typical cyclic α,β-unsaturated enones, such as 2-cyclohexenone, with olefins was performed in moderate to good yields (42-82%) and with high enantioselectivity (82%-96% ee). An unusual substitution pattern at the chiral oxazaborolidine-AlBr3 Lewis acid complex that promotes the reaction was found to be crucial for the success of the reaction. The method was applied to the enantioselective synthesis of the monoterpene (-)-grandisol, which could be accomplished in six steps and with an overall yield of 13% starting from 3-methyl-2-cyclohexenone.
Intramolecular C-H insertion reactions of (η5-Cyclopentadienyl)dicarbonyliron carbene complexes: Scope of the reactions and application to the synthesis of (±)-sterpurene and (±)-pentalenene
Ishii,Zhao,Mehta,Knors,Helquist
, p. 3449 - 3458 (2007/10/03)
(η5-Cyclopentadienyl)dicarbonyliron carbene complexes, [(η5C5H5) (CO)2Fe=CHR]+BF4-, are generated as reactive intermediates from thioether derivatives, (η5-C5H5)(CO)2FeCH(R)SPh, by S-alkylation with trimethyloxonium tetrafluoroborate and loss of thioanisole. The carbene complexes undergo intramolecular C-H insertion into appropriately situated side chains to form cyclopentane derivatives. The reaction has been developed into a general procedure employing cycloalkanones as scaffolds bearing the iron carbene moieties and the side chains at C(2) and C(3), respectively. The products of the intramolecular insertion reactions are substituted bicyclo[n.3.0]alkanones. The scope and limitations of the reaction are described. The reaction is applied to a total synthesis of sterpurene and to a formal synthesis of pentalenene. Overall, this approach to cyclopentane annulation complements the related metal-catalyzed insertion reactions of diazocarbonyl compounds, which are also believed to occur via metal carbene complexes.
A SIMPLE AND EFFICIENT ROUTE TOWARDS USEFULLY FUNCTIONALISED SIX AND SEVEN-MEMBERED RING SYSTEMS VIA α-HYDROXYCYCLOBUTANE REARRANGEMENT FOLLOWED BY RETROALDOL CLEAVAGE
Ranu, Brindaban C.,Sarkar, Dipak C.,Basu, Manas K.
, p. 3107 - 3114 (2007/10/02)
Acid-catalysed rearrangement of α-hydroxycyclobutane derivative 10 followed by retroaldol cleavage and oxidation in an one-pot operation furnishes 1β-methyl-1α,4α-cycloheptane dicarboxylic acid 12 in excellent yield.With proper selection of starting α-hydroxycyclobutane derivative this methodology leads to highly functionalised and fused ring systems 17 and 20 respectively.
A Simple Entry to Functionalised Seven-Membered Ring Systems via α-Hydroxycyclobutane Rearrangement followed by Retroaldol Cleavage
Ranu, Brindaban C.,Sarkar, Dipak C.
, p. 245 - 246 (2007/10/02)
A novel three-step procedure for the synthesis of cycloheptane-1,4-dicarboxylic acid derivatives has been developed exploiting α-hydroxycyclobutane rearrangement and retroaldol cleavage.
