N,N-Dimethylbenzylamine, alkyl and aryl imines derived from benzaldehyde, and 2-phenyl-4,4-dimethyloxazoline all undergo cyclometallation with [IrCl 2 Cp*] 2 (Cp* = η-C 5 Me 5 ) when treated with NaOAc in dichloromethane at room temperature. The imines are also cyclometallated by [RhCl 2 Cp*] 2 under the same conditions whilst only N-alkyl imines are cyclometallated by [RuCl 2 (p-cymene)] 2 . The role of acetate in the cyclometallation is more than just as a base. X-Ray structures of cyclometallated complexes [MCl{C 6 H 4 -2-C(H)᎐ ᎐ NCH 2 CH 2 OMe-κC,N}(η-ring)](M = Ir, Rh ring = Cp*; M = Ru, ring = p-cymene), [MCl{C 6 H 4 -2-C(H)᎐ ᎐ NCH 2 CH 2 OMe-κC,N}Cp*](M = Ir, Rh), [RuCl(η 2 -O 2 CMe)(p-cymene)] and [IrCl 2 (NH 2 Ph)Cp*] are reported.
A series of chiral bipyridine-type ligands 5-12 has been synthesized via a de novo construction of the pyridine nucleus. The chiral moieties of the ligands originate from the monoterpene realm, namely, pinocarvone (13 f 6, 7, and 9), myrtenal (18 f 5), nopinone (21 f 8 and 10), and menthone (28 f 11 and 12); the first three precursors can be obtained in one step from -and R-pinene, respectively. Complexes of these ligands with molybdenum(0) (38-40) and copper(II) (41) have been characterized by single-crystal X-ray crystallography. While complex 38 exhibits polymorphism (monoclinic and tetragonal forms crystallize from the same batch), 41 is characterized by a tetrahedrally distorted geometry of the metal coordination. The Mo and Pd complexes exhibit modest asymmetric induction in allylic substitution (43 f 44), and the Cu(I) counterpart of 41, derived from 10 (PINDY) and Cu(OTf) 2 , shows promising enantioselectivity (49-75% ee) and reaction rate (g30 min at room temperature) in allylic oxidation of cyclic olefins (47 f 48). The Cu(I) complex of 11 (MINDY) proved effective in cyclopropanation (49 f 50) with up to 72% ee.
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