title: Enantioselective Aza Michael-Type Addition to Alkenyl Benzimidazoles Catalyzed by a Chiral Phosphoric Acid.
abstract: Highly enantioselective Michael-type addition (MTA) reactions between N-protected alkenyl benzimidazoles and either pyrazoles or indazoles as nitrogen nucleophiles are accomplished for the first time using chiral phosphoric acid catalyst. Theoretical studies elucidated the reaction pathway and the origin of the stereochemical outcomes, where the catalyst substituent and the N-protecting group of benzimidazole contributed to the resulting high enantioselectivity.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
authors.forename: Ya-Yi
authors.initials: YY
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
authors.forename: Kyohei
authors.initials: K
authors.lastname: Kanomata
authors.affiliation: Department of Chemistry and Bioengineering, Graduate School of Engineering, Iwate University, Morioka, 020-8551, Japan.
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Korenaga
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai, 980-8578, Japan. mterada@m.tohoku.ac.jp.|Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan. mterada@m.tohoku.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Terada
keywords: Michael additions; enantioselectivity; heterocycles; organocatalysis; synthetic methods