Gilles Lemay

Effet du benzene dans la reaction de Grignard sur les nitriles

Resume Use of benzene containing one equivalent of ether as solvent in Grignard reactions of nitriles at room temperature, leads to increased yields of the corresponding ketones compared to results obtained for the same reactions in ether. A useful consequence of this is that undesirable side reactions are virtually eliminated.

A facile and general route to 4-substituted-2 butenolides

Abstract Grignard reagents react with 7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride and produce in high yields the corresponding substituted bicyclo-γ-butanolides. These lactones produce the title compounds by retro Diels-Alder reaction during distillation.

Alkylation des lactones tricycliques pontees. Application a la synthese des butenolides trisubstitues en 2 et 4

Abstract Disubstituted endo tricyclic lactones have been prepared by the reaction of primary alkylmagnesium compounds with the endo bicyclo [ 2.2.1 ] hept-5-ene-2, 3 dicarboxylic anhydride. These lactones were alkylated and transformed into corresponding 3,5,5-trialkyl-2(5H) furanones.

Steric effects ih the reaction of di(bromomagnesio)alkanes with carboxylic esters

Abstract Largely different product distributions were observed on the action of various carboxylic esters with 1,4-di(bromomagnesio)butane and its homologue 1,5-di(bromomagnesio)pentane. The much larger yields of reduction product with the latter are the evidence for the structural geometric requirements for the annelation step.

Reaction of di(bromomagnesio)alkanes with unsymmetrically substituted cyclic anhydrides

Abstract Alkylated γ-spirolactones were prepared in one-step reactions in high yields from butane-1,4-diyl and pentane-1,5 diyldimagnesium dibromides and substituted cyclic anhydrides in tetrahydrofuran. In the light of experimental findings electronic and steric factors influence the regiospecificity of this reaction.

Effet du benzene dans la reaction de grignard sur les cetones encombrees

Abstract The substitution of Benzene or Toluene to ether in the Grignard reaction with hindered ketones leads to a 75% increase of yield.

L'importance de la presence de l'oxygene en position-7 dans les reactions des alkylmagnesiens secondaires avec les anhydrides tricycliques pontes.

Abstract The reaction of secondary alkylmagnesium bromides with endo and exo bicyclo-[2.2.1]hept-5-ene-2,3-dicarboxylic anhydrides lead at the corresponding ketoacids whereas with the 7-oxa exo bicyclo[2.2.1]hept-5-ene-2,3 dicarboxylic anhydride produced only the monosubstituted lactones.