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5 results on '"Menard, F."'

1. Addition of Tethered Nonaromatic Carbon Nucleophiles to Chemoselectively Activated Amides

Author

Belanger, G., Larouche-Gauthier, R., Menard, F., Nantel, M., and Barabe, F.

Abstract

In an effort to develop new ways of synthesizing polycyclic alkaloids, we successfully added silyl enol ethers, allylsilanes, and enamines to iminium ions generated from amides. Because of their higher oxidation state, such iminiums show a yet unexploited advantage of potential double cyclizations over standard Mannich monocyclizations. We report herein the first example of tethered nonaromatic carbon nucleophiles adding to activated amides for the generation of enaminals of various ring sizes, with endo- or exo-cyclic nitrogen.

Published
2005

2. Phosphine-Mediated [4 + 2] Annulation of Bis(enones):  A Lewis Base Catalyzed “Mock Diels−Alder” Reaction

Author

Couturier, M., Menard, F., Ragan, J. A., Riou, M., Dauphin, E., Andresen, B. M., Ghosh, A., Dupont-Gaudet, K., and Girardin, M.

Abstract

Lewis-base-catalyzed cycloisomerization of bis(enones) to decalins has been demonstrated as an alternative to the traditional Lewis acid catalyzed Diels−Alder cycloaddition. In this process, a trialkylphosphine mediates both bond formation steps in two distinct catalytic cycles. The single-pot operation generates two carbon−carbon bonds and up to five contiguous stereocenters in one step, starting from achiral, aliphatic substrates; eight examples are provided.

Published
2004

3. Regioselective rhodium(I)-catalyzed hydroarylation of protected allylic amines with arylboronic acids.

Author

Tsui GC, Menard F, and Lautens M

Subjects
Catalysis, Combinatorial Chemistry Techniques, Molecular Structure, Stereoisomerism, Structure-Activity Relationship, Temperature, Allyl Compounds chemistry, Amines chemistry, Boronic Acids chemistry, Rhodium chemistry
Abstract

A novel regioselective rhodium(I)-catalyzed hydroarylation of unactivated alkenes with arylboronic acids is described. The catalytic system employs [Rh(COD)OH](2) and BINAP to effect the addition of various arylboronic acids to protected allylic amines. The regioselectivity was found to be highly dependent on the protecting group, favoring the linear addition product with up to 92% yield and >20:1 regioselectivity.

Published
2010
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4. Rh(I)-catalyzed carbonylative ring opening of diazabicycles with acyl anion equivalents.

Author

Menard F, Weise CF, and Lautens M

Subjects
Anions, Catalysis, Magnetic Resonance Spectroscopy, Azabicyclo Compounds chemistry, Ketones chemistry, Rhenium chemistry
Abstract

A catalytic desymmetrization of strained alkenes by ring-opening of meso-diazabicycles with acyl anion nucleophiles is reported. Densely functionalized trans-1,2-hydrazinoacyl cyclopentene building blocks are obtained stereoselectively. The acyl anion equivalent is generated in situ under very mild conditions from readily available organoboron precursors.

Published
2007
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5. Rhodium-catalyzed asymmetric allylic substitution with boronic acid nucleophiles.

Author

Menard F, Chapman TM, Dockendorff C, and Lautens M

Subjects
Catalysis, Boronic Acids chemistry, Rhodium chemistry
Abstract

An enantio-, regio-, and diastereoselective rhodium(I)-catalyzed desymmetrization of a meso-cyclic allylic dicarbonate with organoboronic acid nucleophiles is described. The rhodium(I) catalyst formed in situ from [Rh(cod)OH]2 and Xyl-P-PHOS allowed the S(N)2' allylic substitution product to be obtained with a range of arylboronic acids in enantiomeric excesses of up to 92% with regioselectivities of up to >20:1.

Published
2006
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