Lithium Bis(N,N-diethylcarbamoyl)cuprate

(Et2NCO)2CuLi

[71435-48-8]  · C10H20CuLiN2O2  · Lithium Bis(N,N-diethylcarbamoyl)cuprate  · (MW 270.76)

(carbamoylation of organic halides1,2)

Alternate Name: lithium bis[(diethylamino)carbonyl]cuprate.

Solubility: sol THF, HMPA.

Preparative Method: prepared in situ under N2; an equimolar reaction of Copper(I) Chloride and Lithium Diethylamide in a mixed solvent of THF and HMPA (4:1) at -20 °C produced a precipitate of CuNEt2, which was dissolved by an additional 1 equiv of LiNEt2; 2 equiv Carbon Monoxide were absorbed by this homogeneous solution under ambient conditions; the resulting solution was used in the carbamoylation directly.1

Handling, Storage, and Precautions: stable below 80 °C, decomposes partly at 100 °C; air- and moisture-sensitive; handle in a fume hood under inert gas (Ar or N2);1 the hazards of HMPA and CO are well-documented.3

Carbamoylation.

Various organic halides can be carbamoylated by this reagent. The active allyl halide gave a 45% yield of N,N-diethyl-3-butenamide (based on LiNEt2), with concomitant evolution of CO nearly equivalent to copper; the yield was 76% under a CO pressure of 50 kg cm-2. Reaction with acid bromides took place smoothly under mild conditions to produce a-keto amides, but for some less reactive chlorides a higher reaction temperature was required.1 This reaction with acid halides provides an effective method of preparing a-ketoamides (eq 1); several other reagents utilized for direct carbamoylation did not give this functionality.4,5 Lithium N,N-dimethylcarbamoylnickel carbonylate,5f which is effective for the carbamoylation of vinylic and aromatic halides, reacted with acid halides to produce the corresponding amides instead of a-ketoamides. N,N-Diisopropylcarbamoyllithium5c,5e and N,N-dimethylcarbamoyllithium react with aldehydes and ketones readily, but their reaction with acid halides has not been reported.

Under palladium catalysis, the carbamoylation of iodobenzene was optimized.2 A related reagent, Lithium Bis(N-methyl-N-phenylcarbamoyl)cuprate, reacts with iodobenzene with relatively higher yield under the same catalysis conditions (eq 2).

The title reagent undergoes conjugate addition with methyl vinyl ketone to give N,N-diethyllevulinamide in 78% isolated yield, but reaction with cyclohexenone was not successful (eq 3).1

Conversion to Oxamide and Carbamate Derivatives.

Under suitable conditions, lithium bis(N,N-diethylcarbamoyl)cuprate can be converted to the corresponding oxamide, oxamic acid, and carbamate (eqs 4-6).2


1. Tsuda, T.; Miwa, M.; Saegusa, T. JOC 1979, 44, 3734.
2. Wakita, Y.; Noma, S.-Y.; Maeda, M.; Kojima, M. JOM 1985, 297, 379.
3. See, for example: (a) Sax, N. I.; Lewis, R. J. Dangerous Properties of Industrial Materials, 7th ed.; Van Nostrand Reinhold: New York, 1989; Vol. 2, p 713 [CO] and Vol. 3, p 1870 (HMPA). (b) The Sigma-Aldrich Library of Chemical Safety Data, 2nd ed.; Lenga, R. E., Ed.; Sigma-Aldrich: Milwaukee, 1988; Vol. 1, p 685 [CO] and p 1853 (HMPA).
4. Rautenstrauch, V.; Joyeux, M. AG(E) 1979, 18, 83.
5. (a) Schöllkopf, U.; Gerhart, F. AG(E) 1967, 6, 805. (b) Bánhidai, B.; Schöllkopf, U. AG(E) 1973, 12, 836. (c) Schöllkopf, U.; Beckhaus, H. AG(E) 1976, 15, 293. (d) Fraser, R. R.; Hubert, P. R. CJC 1974, 52, 185. (e) Fletcher, A. S.; Smith, K.; Swaminathan, K. JCS(P1) 1977, 1881. (f) Fukuoka, S.; Ryang, M.; Tsutsumi, S. JOC 1971, 36, 2721.

Edward J. Parish & Shengrong Li

Auburn University, AL, USA



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