[3052-45-7]  · C3H5Li  · Allyllithium  · (MW 48.01)

(allylating agent in substitutions and additions; used to attach allyl groups to other metals and nonmetals)

Physical Data: colorless solid, pyrophoric in air.2 Crystals of complex with N,N,N,N,N-Pentamethyldiethylenetriamine showed monomeric ion pairs by X-ray.3 IR,4 Raman,4b UV,5 and 1H,3,6 13C,7 and 7Li8 NMR spectra have been reported on solutions.

Solubility: sol in ethers with degrees of association 1.4-10; sparingly sol in alkanes.2

Form Supplied in: prepared in situ and used directly.

Preparative Methods: from allyl phenyl ether and Li in THF/ether is recommended for large scale, tin-lithium exchange between allyltins and phenyllithium for pure samples.9 Halogen-metal exchange is impractical due to fast Wurtz coupling. Allyllithium can also be made at -78 °C by the reaction of n-Butyllithium with allyl methyl (or phenyl) selenide,10 and by metallating propene with butyllithium.11

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

Nucleophilic Substitutions at Carbon.

Resonance-stabilized Li reagents such as allyllithium are stronger nucleophiles but weaker bases than alkyllithium reagents, permitting displacement of Br- and I- from cyclohexyl and cyclopentyl systems in Wurtz-type couplings (eq 1).12 The allyl group extends chains by three carbon atoms and can be readily converted into many other groupings. Optically active secondary halides and tosylates react with inversion.13

High-yield displacements also occur at the less-hindered carbons of epoxides (eq 2).14

Nucleophilic Substitutions at Other Nonmetals.

Allyllithium reacts with aryl arylsulfonates at sulfur to give allyl aryl sulfones (eq 3).15 Similar reactions occur to produce aryl allyl sulfoximines.16

Additions to Double Bonds.

Allyllithium adds to aldehydes17 and ketones (if aromatic, by electron transfer),18 allylic alcohols (eq 4),19 imines,20 ketenimines,21 thionolactones,22 a,b-unsaturated thioamides (by 1,4-addition),23 and lithium carboxylates.24

Metal Exchange.

Allyllithium is reacted with copper salts to make lithium diallylcuprate, often used for conjugate addition of allyl groups to a,b-unsaturated carbonyl compounds.25

Related Reagents.

Allylcopper; Allylmagnesium Bromide; Crotyllithium; Lithium Diallylcuprate; Methallyllithium.

1. Wakefield, B. J. The Chemistry of Organolithium Compounds; Pergamon: Oxford, 1974.
2. West, P.; Purmort, J. I.; McKinley, S. V. JACS 1968, 90, 797.
3. Schuemann, U.; Weiss, E.; Dietrich, H.; Mahdi, W. JOM 1987, 322, 299.
4. (a) Seyferth, D.; Weiner, M. A. JOC 1961, 26, 4797. (b) Sourisseau, C.; Pasquier, B.; Hervieu, J. Spectrochim. Acta 1975, 31A, 287.
5. Waack, R.; Doran, M. A. J. Phys. Chem. 1964, 68, 1148.
6. (a) Johnson, C. S. Jr.; Weiner, M. A.; Waugh, J. S.; Seyferth, D. JACS 1961, 83, 1306. (b) Brownstein, S.; Bywater, S.; Worsfold, D. J. JOM 1980, 199, 1.
7. (a) van Dongen, J. P. C. M.; van Dijkman, H. W. D.; de Bie, M. J. A. RTC 1974, 93, 29. (b) Schlosser, M.; Lehmann, R.; Jenny, T. JOM 1990, 389, 149.
8. Scherr, P. A.; Hogan, R. J.; Oliver, J. P. JACS 1974, 96, 6055.
9. (a) Eisch, J. J. Organomet. Synth. 1981, 2, 91. (b) Desponds, O.; Schlosser, M. JOM 1991, 409, 93.
10. Clarembeau, M.; Krief, A. TL 1984, 25, 3629.
11. Akiyama, S.; Hooz, J. TL 1973, 4115.
12. Korte, W. D.; Cripe, K.; Cooke, R. JOC 1974, 39, 1168.
13. (a) Sommer, L. H.; Korte, W. D. JOC 1970, 35, 22. (b) Korte, W. D.; Kinner, L.; Kaska, W. C. TL 1970, 603.
14. Marshall, J. A.; Lewellyn, M. JACS 1977, 99, 3508.
15. Baarschers, W. H. CJC 1976, 54, 3056.
16. (a) Harmata, M.; Claassen, R. J. II TL 1991, 32, 6497. (b) Reggelin, M.; Weinberger, H. TL 1992, 33, 6959.
17. Yamamoto, Y.; Komatsu, T.; Maruyama, K. JOM 1985, 285, 31.
18. Yamataka, H.; Kawafuji, Y.; Nagareda, K.; Miyano, N.; Hanafusa, T. JOC 1989, 54, 4706.
19. Felkin, H.; Swierczewski, G.; Tambute, A. TL 1969, 707.
20. Cainelli, G.; Mezzina, E.; Panunzio, M. TL 1990, 31, 3481.
21. Cunico, R. F.; Kuan, C. P. JOC 1992, 57, 3331.
22. Nicolaou, K. C.; McGarry, D. G.; Somers, P. K.; Veale, C. A.; Furst, G. T. JACS 1987, 109, 2504.
23. Tamaru, Y.; Harada, T.; Nishi, S.; Yoshida, Z. TL 1982, 23, 2383.
24. Zadel, G.; Breitmaier, E. AG(E) 1992, 104, 1035.
25. (a) Daviaud, G.; Miginiac, P. TL 1973, 3345. (b) Hutchinson, D. K.; Fuchs, P. L. TL 1986, 27, 1429.

Robert B. Bates & Sriyani Caldera

University of Arizona, Tucson, AZ, USA

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