81509-24-2Relevant academic research and scientific papers
Catalytic Carbochlorocarbonylation of Unsaturated Hydrocarbons via C?COCl Bond Cleavage**
Boehm, Philip,Denton, Elliott H.,Fellert, Maximilian,Lee, Yong Ho,Morandi, Bill,Roediger, Sven
, p. 23435 - 23443 (2021/09/20)
Here we report a palladium-catalysed difunctionalisation of unsaturated C?C bonds with acid chlorides. Formally, the C?COCl bond of an acid chloride is cleaved and added, with complete atom economy, across either strained alkenes or a tethered alkyne to generate new acid chlorides. The transformation does not require exogenous carbon monoxide, operates under mild conditions, shows a good functional group tolerance, and gives the isolated products with excellent stereoselectivity. The intermolecular reaction tolerates both aryl- and alkenyl-substituted acid chlorides and is successful when carboxylic acids are transformed to the acid chloride in situ. The reaction also shows an example of temperature-dependent stereodivergence which, together with plausible mechanistic pathways, is investigated by DFT calculations. Moreover, we show that benzofurans can be formed in an intramolecular variant of the reaction. Finally, derivatisation of the products from the intermolecular reaction provides a highly stereoselective approach for the synthesis of tetrasubstituted cyclopentanes.
Enzymatic kinetic resolution of aromatic substituted norbornene mono-esters using pig's liver esterase
Mamaghani
, p. 147 - 151 (2007/10/03)
Pig's liver esterase (PLE) has been used as a chiral catalyst in the enzymatic kinetic resolution of aromatic substituted norbornene mono-esters, methyl 3-endo-phenylbicyclo[2.2.1]hept-5-ene-2-exo-carboxylate and its endo-counterpart, methyl 3-endo-p-nitro-phenyl-bicyclo[2.2.1]hept-5-ene-2-exo-carboxylate and methyl 3-endo-benzoylbicyclo[2.2.1]hept-5-ene-2-exo-carboxylate. In this study a range of low to high enantioselectivities (83% ee) was observed. The effect of co-solvents has also been examined.
A study on the effect of Lewis acid catalysis on the molecular mechanism of the cycloaddition between (E)-methyl cinnamate and cyclopentadiene
Alves,Camilo,Gruber,Da Silva
, p. 6877 - 6883 (2007/10/03)
The molecular mechanism of the Diels-Alder reaction between (E)-methyl cinnamate and cyclopentadiene has been analyzed by means of AM1 semiempirical method and compared to the experimental results. Stationary points for two reactive channels, endo-cis and exo-cis, on potential energy surfaces have been characterized. Three Lewis acids, boron trifluoride (BF3), aluminum trichloride (AlCl3) and catechol boron bromide (CBB) have been used as catalysts taking into account the formation of a complex between the boron or aluminum atom and the carbonyl oxygen of (E)-methyl cinnamate. The molecular mechanism of the uncatalyzed reaction corresponds to a concerted process. In the presence of BF3 and AlCl3, enhancement of both the asynchronicity and charge transfer, with small decreased energy barriers, were obtained. With CBB, the molecular mechanism changes and the reaction takes place along a stepwise mechanism. The initial step corresponds to the nucleophilic attack of cyclopentadiene on the dienophile double bond to give an intermediate, followed by its closure in the second step, yielding the corresponding final cycloadduct. The inclusion of the CBB catalyst drastically decreases the energy barrier associated with the carbon-carbon bond formation of the first step, relative to the concerted process. The role of the Lewis acid catalyst emerges from the analysis of the results.
