Copper(II) Nitrate-(±)-1-Phenylethylamine1


[10031-43-3]  · CuN2O6  · Copper(II) Nitrate-(±)-1-Phenylethylamine  · (MW 241.60) ((±)-PhCH(Me)NH2)

[618-36-0]  · C8H11N  · Copper(II) Nitrate-(±)-1-Phenylethylamine  · (MW 121.18)

(reagent for the oxidative coupling of phenols2)

Physical Data: Cu(NO3)2.3H2O: mp 114 °C. (±)-1-Phenylethylamine: bp 185 °C/756 mmHg; d 0.95 g cm-3. The exact structure of the copper(II) complex is unknown; the number of phenylethylamine ligands is preferentially 4 (n = 4).

Form Supplied in: the reagent is prepared in situ; both compounds are commercially available. (±)-1-Phenylethylamine is a colorless oil; copper(II) nitrate trihydrate is a blue crystalline deliquescent material.

Analysis of Reagent Purity: Cu(NO3)2.3H2O: > 99%. (±)-1-Phenylethylamine: 1H NMR (CDCl3, 200 MHz) d 1.37 (d, J = 6.4 Hz, 3H), 4.07 (q, J = 6.7 Hz, 1H), 7.19-7.33 (m, 5H); 13C NMR (CDCl3, 50.29 MHz) d 25.2 (q), 50.8 (d), 125.2 (d), 126.3 (d), 127.9 (d), 147.3 (s).

Preparative Methods: prepared in situ by complexation of copper(II) nitrate with 4 equiv of (±)-1-phenylethylamine in methanol under inert atmosphere.1,2

Handling, Storage, and Precautions: (±)-1-phenylethylamine is stable when stored in a sealed container under nitrogen.

General Considerations.

The copper(II) nitrate-(±)-1-phenylethylamine reagent (1) is a typical example of a number of copper(II) amine oxidizing agents.1-3 Reagent (1) can effect the oxidative coupling of phenols under anaerobic conditions. Both C-C and C-O coupled products can be obtained. Characteristic examples are given.

Synthesis of Dehydrogriseofulvin.

Reaction of (1) with bisphenols leads to intramolecular C-O coupled products (eq 1).1

Synthesis of 1,1-binaphthalene-2,2-diols.

The oxidative dimerization of 2-naphthols with (1) provides 1,1-binaphthols (eq 2).2

Unsymmetrical 1,1-binaphthalene-2,2-diols are formed in 80-97% yield by oxidative cross-coupling of differently substituted 2-naphthols mediated by related CuII-primary amine complexes.3b (S)-(-)-1,1-Binaphthalene-2,2-diol and (S)-(-)-10,10-dihydroxy-9,9-biphenanthryl have been prepared with optical purities up to 98% by a similar oxidative coupling using chiral nonracemic primary amines.1,3a,3d

1. Feringa, B.; Wynberg, H. Bioorg. Chem. 1978, 7, 397.
2. Feringa, B.; Wynberg, H. TL, 1977, 4447.
3. (a) Brussee, J.; Groenendijk, J. L. G.; te Koppele, J. M.; Jansen, A. C. A. T 1985, 41, 3313. (b) Hovorka, M.; Závada, J. T 1992, 48, 9517. (c) Hovorka, M.; &SSbreve;&cbreve;igel, R.; Gunterová, J.; Tichý, M.; Závada, J. T 1992, 48, 9503. (d) Yamamoto, K.; Fukushima, H.; Nakazaki, M. JCS(C) 1984, 1490.

Ben L. Feringa & E. Marc Veen

University of Groningen, The Netherlands

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