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)
Laccase (EC 1.10.3.2) and tyrosinases (EC 1.14.18.1) 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)
high enantioselectivity and good yield were observed for aryl methyl ketones, with a modest drop in enantioselectivity for electron-poor sub-strates. Other aryl ketones gave rise to good to excellent e.r.'s, as highlighted by substrate 2h. Heteroaromatics were also well tolerated under the reaction conditions, with thiophene-and furan-derived ketones(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)
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)
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)
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)
An exploration into the origin of chemoselectivity in the NHC-catalyzed cross-benzoin reaction reveals several key factors governing the preferred pathway. In the first computational study to explore the cross-benzoin reaction, a piperidinone-derived triazolium catalyst produces kinetically controlled chemoselectivity. This is supported by (1)H NMR studies(More)