title: anti-Selective catalytic asymmetric nitroaldol reaction via a heterobimetallic heterogeneous catalyst.
abstract: Full details of an anti-selective catalytic asymmetric nitroaldol reaction promoted by a heterobimetallic catalyst comprised of Nd(5)O(O(i)Pr)(13), an amide-based ligand, and NaHMDS (sodium hexamethyldisilazide) are described. A systematic synthesis and evaluation of amide-based ligands led to the identification of optimum ligand 1m, which provided a suitable platform for the Nd/Na heterobimetallic complex. During the catalyst preparation in THF, a heterogeneous mixture developed and centrifugation of the suspension allowed for separation of the precipitate, which contained the active catalyst and which could be stored for at least 1 month without any loss of catalytic performance. The precipitate promoted a nitroaldol (Henry) reaction for a broad range of nitroalkanes and aldehydes under heterogeneous conditions, affording the corresponding 1,2-nitroalkanol in a highly anti-selective (up to anti/syn = >40/1) and enantioselective manner (up to 98% ee). Inductively coupled plasma (ICP) and X-ray fluorescence (XRF) analyses revealed that the precipitate indeed included both neodymium and sodium, which was further supported by high-resolution ESI TOF MS spectrometry.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nitabaru
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nojiri
authors.forename: Makoto
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Naoya
authors.initials: N
authors.lastname: Kumagai
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Shibasaki
mesh_terms: D000447:Aldehydes / Q000138:chemical synthesis*; D000473:Alkanes / Q000138:chemical synthesis*; D002384:Catalysis; D017646:Organosilicon Compounds / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000447:Aldehydes; D000473:Alkanes; D017646:Organosilicon Compounds; C116609:3-hydroxybutanal; C024548:hexamethylsilazane