Methallyllithium

[61777-16-0]  · C4H7Li  · Methallyllithium  · (MW 62.05)

(methallylating agent in substitutions and additions; used to attach methallyl groups to other metals and nonmetals)

Alternate Name: 3-lithio-2-methylpropene.

Physical Data: colorless crystals;1 1H, 13C, and 6Li NMR spectra have been reported on solutions.2

Solubility: sol ethers; sparingly sol hydrocarbons.1

Preparative Methods: TMEDA complex by metalating Isobutene with n-Butyllithium/N,N,N,N-Tetramethylethylenediamine;3 by metalating isobutene with butyllithium/Potassium t-Butoxide, and then reacting the methallylpotassium with Lithium Bromide in ether;4 from methallyltin compounds by exchange with Phenyllithium or butyllithium.1

Form Supplied in: prepared in situ and used directly.

Handling, Storage, and Precautions: must be prepared and transferred under inert gas to exclude oxygen and moisture.

Reactions.

Resonance-stabilized Li reagents such as methallyllithium are stronger nucleophiles but weaker bases than alkyllithium reagents, permitting displacement of halides from alkyl halides in Wurtz-type couplings (eq 1).3 Additions to aldehydes and ketones,3a epoxides, and Carbon Dioxide also go well.4 Methallyllithium has been used as a source of methallyl groups attached to boron5 (useful in the synthesis of chiral homoallylic alcohols as shown in eq 2) and transition metals.6 On heating, methallyllithium disproportionates, giving off isobutene and providing a source of dilithiotrimethylmethane (eq 3).7

Related Reagents.

Table 1 lists some useful methallyllithium derivatives.3b,7-22 See also Allyllithium and Allylmagnesium Bromide.


1. Gampe, D.; Jacob, K.; Thiele, K. H. ZC 1985, 25, 151.
2. Fraenkel, G.; Winchester, W. R. JACS 1989, 111, 3794.
3. (a) Akiyama, S.; Hooz, J. TL 1973, 4115. (b) Klein, J.; Medlik, A. CC 1973, 275.
4. Schlosser, M.; Hartmann, J. AG(E) 1973, 12, 508.
5. Jadhav, P. K.; Bhat, K. S.; Perumal, P. T.; Brown, H. C. JOC 1986, 51, 432.
6. (a) Gampe, D.; Jacob, K.; Thiele, K. H. Z. Anorg. Allg. Chem. 1985, 526, 36. (b) Lehmkuhl, H.; Naeser, J.; Mehler, G.; Keil, T.; Danowski, F.; Benn, R.; Mynott, R.; Schroth, G.; Gabor, B.; Krueger, C.; Betz, P. CB 1991, 124, 441.
7. Ludvig, M. M.; Kawa, H.; Lagow, R. J. SC 1990, 20, 1657.
8. Schlosser, M.; Staehle, M. AG(E) 1980, 19, 487.
9. Cazes, B.; Julia, S. TL 1978, 4065.
10. Fitt, J. J.; Gschwend, H. W. JOC 1981, 46, 3349.
11. Carlson, R. M. TL 1978, 111.
12. Marx, J. N.; Bih, Q. R. JOC 1987, 52, 336.
13. Cardillo, G.; Contento, M.; Sandri, S. TL 1974, 25, 2215.
14. White, J. D.; Reddy, G. N.; Spessard, G. O. JACS 1988, 110, 1624.
15. (a) Bates, R. B.; Beavers, W. A.; Gordon, B. III; Mills, N. S. JOC 1979, 44, 3800. (b) Bates, R. B.; Gordon, B. III; Keller, P. C.; Rund, J. V.; Mills, N. S. JOC 1980, 45, 168.
16. (a) Klusener, P. A. A.; Hommes, H. H.; Verkruijsse, H. D.; Brandsma, L. CC 1985, 1677. (b) Semmelhack, M. F.; Fewkes, E. J. TL 1987, 28, 1497.
17. Kulik, W.; Verkruijsse, H. D.; de Jong, R. L. P.; Hommes, H.; Brandsma, L. TL 1983, 24, 2203.
18. Eidenschink, R.; Kauffmann, T. AG(E) 1972, 11, 292.
19. Bannwarth, W.; Eidenschink, R.; Kauffmann, T. AG(E) 1974, 13, 468.
20. Thomas, E. W. TL 1983, 24, 1467.
21. Wilson, S. R.; Phillips, L. R.; Natalie, K. J. Jr. JACS 1979, 101, 3340.
22. Cohen, T.; Guo, B. S. T 1986, 42, 2803.

Robert B. Bates & Sriyani Caldera

University of Arizona, Tucson, AZ, USA



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