A novel organocatalytic method for the stereoselective synthesis of highly substituted cyclopropanes is reported. The Michael adducts, generated through the addition of alpha-substituted cyanoacetates to easily accessible vinyl selenones catalyzed by a bifunctional ureidic catalyst, smoothly cyclize by intramolecular alkylation induced by a de-ethoxycarbonylation process. The one-pot sequence generates cyclopropanes bearing adjacent tertiary and quaternary stereocentres as single Z-isomers in moderate to high yields and good enantiomeric excesses.
A New Stereoselective Synthesis of Cyclopropanes Containing Quaternary Stereocentres via Organocatalytic Michael Addition to Vinyl Selenones.
MARINI, Francesca
;STERNATIVO, Silvia;DEL VERME, FRANCESCA;TESTAFERRI, Lorenzo;TIECCO, Marcello
2009
Abstract
A novel organocatalytic method for the stereoselective synthesis of highly substituted cyclopropanes is reported. The Michael adducts, generated through the addition of alpha-substituted cyanoacetates to easily accessible vinyl selenones catalyzed by a bifunctional ureidic catalyst, smoothly cyclize by intramolecular alkylation induced by a de-ethoxycarbonylation process. The one-pot sequence generates cyclopropanes bearing adjacent tertiary and quaternary stereocentres as single Z-isomers in moderate to high yields and good enantiomeric excesses.File in questo prodotto:
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