537708-74-0Relevant academic research and scientific papers
Enantioselective, Palladium-Catalyzed Conjugate Additions of Arylboronic Acids to Form Bis-benzylic Quaternary Stereocenters
Kadam, Abhishek A.,Ellern, Arkady,Stanley, Levi M.
, p. 4062 - 4065 (2017)
We report enantioselective, palladium-catalyzed conjugate additions of arylboronic acids to β-aryl, β,β-disubstituted enones to generate ketones containing bis-benzylic quaternary stereocenters. A catalyst generated from palladium trifluoroacetate and (S)-4-tert-butyl-2-(2-pyridyl)oxazoline ligand ((S)-t-BuPyOx) promotes conjugate additions of a wide range of arylboronic acids to a variety of β-aryl, β,β-disubstituted enones. Iterative addition of the arylboronic acid to minimize undesired protodeboronation pathways leads to efficient formation of the corresponding ketones containing bis-benzylic quaternary stereocenters in up to 92% yield and up to 93% enantioselectivity.
Palladium-Catalyzed Conjugate Addition of Arylboronic Acids to β,β-Disubstituted Enones in Aqueous Media: Formation of Bis-benzylic and ortho-Substituted Benzylic Quaternary Centers
Van Zeeland, Ryan,Stanley, Levi M.
, p. 5203 - 5206 (2015/09/15)
Palladium-catalyzed conjugate addition of arylboronic acids to β,β-disubstituted enones in aqueous media is reported. Additions of a wide range of arylboronic acids to β,β-disubstituted enones occur to form ketone products bearing benzylic all-carbon quaternary centers. These reactions are promoted by a simple catalyst prepared from palladium trifluoracetate and 2,2′-bipyridine. The use of aqueous sodium trifluoracetate as the reaction medium significantly enhances reactivity and enables the formation of challenging bis-benzylic and ortho-substituted benzylic all-carbon quaternary centers.
An experimental and theoretical study of the type C enone rearrangement: Mechanistic and exploratory organic photochemistry
Zimmerman, Howard E.,Nesterov, Evgueni E.
, p. 5422 - 5430 (2007/10/03)
We recently described a new photochemical rearrangement which we termed a Type C process. The reaction involves a δ to α aryl migration in 5-disubstituted cyclohexenones also having bulky C-3 substituents. In contrast to most cyclohexenone rearrangements, the reaction occurs via a twisted π-π* excited triplet rather than the usual n-π* state. The electronic nature of the rearrangement was assessed using migration selectivity with p-anisyl and p-cyanophenyl groups. A synthesis of the reactants was elaborated, and the product structures were established by X-ray and NMR analysis. The reaction mechanism was established further with DFT and CASSCF computations. In the latter, localized NBO basis orbitals permitted proper selection of the active space. The nature of the diradical intermediates as well as the transition states was established computationally. Sensitization experiments with regioselectivities the same as those in direct irradiation confirmed the triplet multiplicity of the process.
