title: Chiral Bis(imidazolidine)-Derived NCN Pincer Rh Complex for Catalytic Asymmetric Mannich Reaction of Malononitrile with N-Boc Imines.
abstract: Chiral bis(imidazolidine)-derived NCN-rhodium complexes ([PhBidine-RhX2 ] and [tBu-PhBidine-RhX2 ]) were prepared by a CH insertion method, and the structures were unequivocally determined by X-ray crystallographic analysis. The [tBu-PhBidine-Rh(OAc)2 ] complex smoothly catalyzed an asymmetric Mannich reaction of malononitrile with N-Boc imines to give products in up to 94 % ee, which are useful for the synthesis of chiral α-amino acids.
authors.affiliation: Molecular Chirality Research Center, Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522 (Japan). tarai@faculty.chiba-u.jp.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Arai
authors.affiliation: Molecular Chirality Research Center, Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522 (Japan).
authors.forename: Takuma
authors.initials: T
authors.lastname: Moribatake
authors.affiliation: Center for Analytical Instrumentation, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522 (Japan).
authors.forename: Hyuma
authors.initials: H
authors.lastname: Masu
keywords: asymmetric catalysis; malononitrile; pincer complexes; rhodium