Bifunctional organocatalysts for the asymmetric synthesis of axially chiral benzamides
نویسندگان
چکیده
Bifunctional organocatalysts bearing amino and urea functional groups in a chiral molecular skeleton were applied to the enantioselective synthesis of axially chiral benzamides via aromatic electrophilic bromination. The results demonstrate the versatility of bifunctional organocatalysts for the enantioselective construction of axially chiral compounds. Moderate to good enantioselectivities were afforded with a range of benzamide substrates. Mechanistic investigations were also carried out.
منابع مشابه
Organocatalytic atroposelective synthesis of axially chiral styrenes
Axially chiral compounds are widespread in biologically active compounds and are useful chiral ligands or organocatalysts in asymmetric catalysis. It is well-known that styrenes are one of the most abundant and principal feedstocks and thus represent excellent prospective building blocks for chemical synthesis. Driven by the development of atroposelective synthesis of axially chiral styrene der...
متن کاملSynthesis of Chiral Thiourea-Phosphine Organocatalysts derived from L-Proline
A novel class of thiourea-phosphine was prepared from L-Proline as a chiral renewable resource. The original structure of the chiral framework offers an interesting potential to the construction of bifunctional organocatalysts for asymmetric transformations.
متن کاملCombinatorial synthesis of functionalized chiral and doubly chiral ionic liquids and their applications as asymmetric covalent/non-covalent bifunctional organocatalysts.
A facile combinatorial strategy was developed for the construction of libraries of functionalized chiral ionic liquids (FCILs) including doubly chiral ionic liquids and bis-functional chiral ionic liquids. These FCIL libraries have the potential to be used as asymmetric catalysts or chiral ligands. As an example, novel asymmetric bifunctional catalysts were developed by simultaneously incorpora...
متن کاملBinaphthyl-based chiral bifunctional organocatalysts for water mediated asymmetric List-Lerner-Barbas aldol reactions.
Novel binaphthyl-based chiral bifunctional organocatalysts were designed, synthesized and successfully applied to the asymmetric List-Lerner-Barbas aldol reaction in the presence of water. These organocatalysts were found to be effective catalysts for the reactions of symmetrical, unsymmetrical and cyclic ketones with different aldehydes to give the corresponding aldol products with higher yiel...
متن کاملPyrrolidinyl-sulfamide derivatives as a new class of bifunctional organocatalysts for direct asymmetric Michael addition of cyclohexanone to nitroalkenes.
A series of chiral pyrrolidinyl-sulfamide derivatives have been identified as efficient bifunctional organocatalysts for the direct Michael addition of cyclohexanone to a wide range of nitroalkenes. The desired Michael adducts were obtained in high chemical yields and excellent stereoselectivities (up to 99/1 dr and 95% ee).
متن کامل