Claude Y. Legault

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Selectivity of the palladium-catalyzed cross-coupling reactions of heterocycles bearing multiple identical halogens is mainly determined by the relative ease of oxidative addition. This is related to both the energy to distort the carbon halogen bond to the transition-state geometry (related to the CX bond-dissociation energy) and to the interaction between(More)
Removal of pharmaceuticals (PhCs) by photocatalysis is a promising avenue in water treatment. The efficiency of these treatments on PhC derivatives compared to their parent molecules remains poorly documented. The present study investigates the efficiency of photodegradation catalyzed by TiO₂ and ZnO nanoparticles on the removal of carbamazepine (CBZ) and(More)
Laccase (EC and tyrosinases (EC are ubiquitous enzymes present in nature as they are known to originate from bacteria, fungi, plants, etc. Both laccase and tyrosinase are copper-containing phenoloxidases requiring readily available O2 without auxiliary cofactor for their catalytic transformation of numerous phenolic substrates. In the(More)
QuantumMechanical Investigations of Organocatalysis: Mechanisms, Reactivities, and Selectivities Paul Ha-Yeon Cheong, Claude Y. Legault, Joann M. Um, Nihan C-elebi-€ Olc-€um, and K. N. Houk* Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States Department of Chemistry, University of Sherbrooke, 2500(More)
[Rh(CO)2Cl]2-Catalyzed (5 + 2) Cycloaddition Reactions with Vinylcyclopropanes Zhi-Xiang Yu,*,‡ Paul Ha-Yeon Cheong,† Peng Liu,† Claude Y. Legault,† Paul A. Wender,*,§ and K. N. Houk*,† Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, College of(More)
We have developed an efficient catalytic enantioselective hydrogenation of pyridine derivatives. Enhanced reactivity was possible by an optimization of the electronic properties of the catalyst through ligand modification. This methodology shows the particular reactivity of N-iminopyridinium ylides that provides access to substituted piperidines in good(More)
An efficient two-step synthesis of O-(2,4-dinitrophenyl)hydroxylamine is described along with a comparison of its aminating efficiency with O-mesitylenesulfonylhydroxylamine (MSH). It was used in an expedient N-amination/benzoylation procedure involving various substituted pyridines, leading to polysubstituted N-benzoyliminopyridinium ylides, and the scope(More)
Unprecedented regioselectivities were observed for the addition of different organometallic nucleophiles to N-benzoyliminopyridinium ylides. Even benzylic and branched aliphatic Grignard reagents, which usually give substantial amounts of 1,4-adducts, showed excellent 1,2-regioselectivities. The electronic nature of the pyridinium ylide is taken into(More)
The synthesis of α-substituted carbonyl compounds is of great importance due to their ubiquity in both natural and man-made biologically active compounds. The field of hypervalent iodine chemistry has been a great contributor to access these molecules. For example, the α-oxidation of carbonyl compounds has been one of the most investigated(More)