Reaction of di(bromomagnesio)alkanes with unsymmetrically substituted cyclic anhydrides
作者:Persephone Canonne、Gilles Lemay、Denis Bélanger
DOI:10.1016/s0040-4039(00)93679-7
日期:1980.1
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 cyclicanhydrides in tetrahydrofuran. In the light of experimental findings electronic and steric factors influence the regiospecificity of this reaction.
Synthetic Applications of the β-Lithiation of β-Aryl Secondary Amides: Diastereoselective and Enantioselective Substitutions
作者:Gary P. Lutz、Hua Du、Donald J. Gallagher、Peter Beak
DOI:10.1021/jo952223r
日期:1996.1.1
The sequence of beta-lithiation and electrophilic substitution of beta-aryl secondary amides is reported. The lithiations occur regioselectively at the beta-position, and the resulting lithiated intermediates can be reacted with a wide range of electrophiles to give substituted products. Reactions of beta-lithiated amides bearing an alpha-substituent provide substituted products with high diastereoselectivity, Electrophilic substitutions of beta-lithiated N-methylamides in the presence of the chiral diamine (-)-sparteine provide highly enantioenriched products. The methodology is used to synthesize enantioenriched beta-aryl beta-substituted amides, acids, and lactones.