COPPER(II) TRIFLUOROMETHANESULFONATE

Reaction

1. Ring-Opening of epoxides and aziridines.
2. Asymmetric conjugate addition of organozinc reagents to α,β-unsaturated ketones.
3. Electrophilic addition of olefins.
4. Asymmetric aziridination of olefins.
5. Asymmetric cycloadditions and aldol condensations.
6. Asymmetric Kharasch oxidation.
7. Asymmetric Michael addition of enamides.
8. Asymmetric O-H or O-R insertion reactions.
9. Enantioselective intramolecular aminooxygenation of alkenes.
10. Enantioselective addition of dialkylzinc reagents to N-acylpyridinium salts.
11. Pd-catalyzed C-H functionalizations of oximes with arylboronic acids.
12. Used as a Lewis acid in the Nazarov cyclization.
13. Catalyst in the diacetoxylation olefins.
14. Catalyst in the meta-selective direct arylation of α-aryl carbonyl compounds.
15. Catalyst in the three-component coupling of amines, aldehydes, and alkynes.

Chemical Properties

white to slightly blue or light grey cryst. powder

Uses

Copper(II) trifluoromethanesulfonate is a mild lewis acid. It is used as catalyst which promotes dehydration of alcohols and diols to alkenes at ambient temperatures. It is widely used to generate carbenoid species from ?-diazo esters and ketones, via in situ reduction to the Cu(I) species. It is also promotes the reaction between diazo esters and imines to give aziridines. It catalyzes syn-selective aldol condensation of (Z)-silyl enol ethers with aldehydes, Friedel-Crafts alkylation, acylation reactions of aromatics and addition of trimethylsilyl cyanide to carbonyl compounds.

Preparation

Copper(II) trifluoromethanesulfonate is prepared from copper(II) carbonate and triflic acid (Trifluoromethanesulfonic Acid) in MeCN.

Purification Methods

Dissolve it in MeCN, add dry Et2O until cloudy and cool at -20o in a freezer. The light blue precipitate is collected and dried in a vacuum oven at 130o/20mm for 8hours. It has 737nm ( 22.4 max M1cm -1) in AcOH. [Salomon & Kochi J Am Chem Soc 95 330 1973]. It has also been dried in a vessel at 0.1Torr by heating with a Fischer burner [Andrist et al. J Org Chem 43 3422 1978]. It has been dried at 110-120o/5mm for 1hour before use and forms a *benzene complex which should be handled in a dry box because it is air sensitive [Kobayashi et al. Chem Pharm Bull Jpn 28 262 1980, Salomon & Kochi J Am Chem Soc 95 330 1973]. [Beilstein 3 IV 34.]