An efficient chiral copper catalytic system [(R)‐(+)‐1,1′‐binaphthyl‐2,2′‐diamine‐copper(I) chloride‐TEMPO] for the asymmetric oxidative coupling of 2‐naphthol derivatives to synthesize enantiomerically enriched BINOL derivatives has been developed with good to excellent enantiomeric excess (up to 97% ee). The addition of a catalytic quantity of 2,2,6,6‐tetramethylpiperidin‐1‐yl oxyl (TEMPO) to the copper‐(R)‐(+)‐1,1′‐binaphthyl‐2,2′‐diamine complex greatly enhanced the reactivity and enantioselectivity of the enantioselective oxidative coupling of 2‐naphthol derivatives and also reduced the reaction temperature from 90 °C to room temperature in dichloromethane solvent.magnified image

Single crystal EPR and optical studies of Cu(II) doped ZnNH 4 PO 4 Á6H 2 O (Zinc struvite) have been carried out at room and liquid nitrogen temperatures. The g and A tensors indicate that the impurity has entered the lattice substitutionally.Even though the coordination polyhedron around the host Zn(II) is a compressed octahedron of oxygen atoms of water, the Cu(II) ion has an elongated octahedron corresponding to d x 2 Ày 2 ground state.The optical spectrum shows four bands at 1205, 1095, 833 and 805 nm, which con¢rms the octahedral coordination of Cu(II) with rhombic (C 2V ) distortion.

No abstract

Enantioselective Oxidative Coupling of 2-Naphthol Derivatives by Copper--(R)-1,1'-binaphthyl-2,2'-diamine-TEMPO Catalyst. -Addition of TEMPO to the (R)-BINAM-CuCl complex is crucial as it increases dramatically the reaction rate and selectivity of the reaction at room temperature. -(ALAMSETTI, S. K.; POONGUZHALI, E.; GANAPATHY, D.; SEKAR*, G.; Adv. Synth. Catal. 355 (2013) 14-15, 2803-2808, http://dx.doi.org/10.1002/adsc.201300513 ; Dep. Chem., Indian Inst. Technol., Chennai 600 036, India; Eng.) -Y. Steudel 13-102

Key indicatorsSingle-crystal X-ray study T = 293 K Mean (C-C) = 0.002 Å R factor = 0.053 wR factor = 0.169 Data-to-parameter ratio = 18.4For details of how these key indicators were automatically derived from the article, see