[1461-22-9]  · C12H27ClSn  · Tri-n-butylchlorostannane  · (MW 325.55)

(precursor of other organotributyltin reagents;1 allylic tributyltins for the diastereoselective synthesis of homoallyl alcohols;2 tributyltin enolates for alkylation3 and regioselective C-C bond formation4)

Alternate Name: tributyltin chloride.

Physical Data: bp 171-173 °C/25 mmHg; n20D 1.400; d 1.200 g cm-3; fp >110 °C.

Form Supplied in: colorless liquid; widely available.

Solubility: sol ether, THF, hexane, CH2Cl2, MeOH.

Handling, Storage, and Precautions: in general, tributyltin compounds are highly toxic. The LD50 value for oral administration of Bu3SnCl to rats is 122-349 mg g-1. This reagent is absorbed through the skin to induce temporary skin burns. It must be handled with gloves in a well-ventilated hood. The reagent is air-stable, but slowly decomposes in presence of moisture.

Precursor to other Tributyltin Reagents.

Since the chlorine atom can be readily replaced by a variety of nucleophiles, tributyltin chloride is widely used for the preparation of other synthetically useful organotin compounds1 such as Tri-n-butylstannane,5 Tri-n-butyl(methoxy)stannane,6 diethylaminotributyltin,7 Cyanotributylstannane,8 Tri-n-butyltin Azide,9 Hexabutyldistannane,10 and Bis(tri-n-butyltin) Oxide (eq 1).11

Tri-n-butylstannyllithium is readily prepared by the treatment of tributyltin chloride with Lithium metal12 and is a valuable reagent for the preparation of organotin compounds.1a The stannyllithium is also prepared from n-Bu3SnH and Lithium Diisopropylamide, or from Bu3SnSnBu3 and n-Butyllithium. Among these preparative methods, the procedure using n-Bu3SnH provides the highest yield of n-Bu3SnLi.10a The reaction of the stannyllithium reagent with aldehydes followed by alcohol protection affords a-alkoxystannanes, which are treated with n-butyllithium to yield a-alkoxyllithium derivatives (eq 2).14 Tri-n-butylstannylcopper (or cuprate) reagents are prepared from the stannyllithium and copper salts.15 These reagents are employed for the preparation of b-stannyl-a,b-unsaturated carbonyl compounds (eq 3).16

Allyl-, Alkenyl-, and Alkynyltin Reagents.

Simple allyltins are prepared by the reaction of Grignard reagents with tributyltin chloride.17 g-Alkoxyallyltins are obtained by trapping the allyl anions generated from allyl ethers.2a In this case, tributyltin chloride attacks the g-position of the allyl anions to produce the (Z)-allyltins, owing to the strong coordination ability of the oxygen atom toward the lithium atom. g-Methoxyallyltin reacts with aldehydes in the presence of Lewis acids to give syn-1,2-diol derivatives with high diastereoselectivity (eq 4).2 An intramolecular allylic tin-aldehyde condensation has been applied to the synthesis of medium-ring cyclic ethers (eq 5).18

Tributyltin chloride reacts with alkenylcopper reagents, generated by the reaction of alkylcoppers and terminal alkynes, to give (Z)-alkenyltin derivatives (eq 6).19 In contrast, the reaction of the alkenylaluminum obtained by hydroalumination affords the (E)-isomer (eq 7).20 Dienyltin derivatives are prepared via the hydrozirconation of 1-en-3-yne.21 Terminal alkynes react with n-Bu3SnAlEt2, prepared in situ from n-Bu3SnLi and Diethylaluminum Chloride, in the presence of CuI or Pd0 catalysts, to give 1,2-dimetallo-1-alkenes with high regio- and stereoselectivity. These intermediates can be selectively functionalized at the vinyl-aluminum bond to provide alkenyltins (eq 8).13

Alkynyltins are easily made by the reaction of lithium or sodium acetylides with tributyltin chloride.22 These compounds undergo coupling with vinyl iodides in the presence of a palladium catalyst to give conjugated enynes (eq 9).

Tin Enolates.

Tin enolates prepared by transmetalation of lithium enolates with tributyltin chloride undergo rapid aldol condensations with aldehydes (eq 10).23 This approach has been used to enhance the yield of the alkylation of the enolate generated by the conjugate addition of lithium enolate to cyclopentenone (eq 11).3 A complicated mixture is obtained in the absence of the tin reagent.

The reaction of lithium dienolates with tributyltin chloride gives g-stannylated a,b-unsaturated esters, which are stable enough to be isolated by distillation (eq 12).4 The aldol-type condensation of the tin-masked dienolates proceeds at the a-position of the dienolates with high regio- and stereoselectivity in the presence of Lewis acid.4a,b On the other hand, the palladium-catalyzed coupling reaction with organic halides takes place at the position directly bonded to tin.4a,c

Related Reagents.

Tributyltin chloride is used more frequently than Chlorotrimethylstannane, perhaps owing to its lower toxicity. The latter reagent is useful in reactions which require a sterically compact trialkylstannyl substituent. See also Chlorotriphenylstannane.

1. (a) Pereyre, M.; Quintard, J. P.; Rahm, A. Tin in Organic Synthesis; Butterworth: London, 1987. (b) Davies, A. G.; Smith, P. J. In Comprehensive Organometallic Chemistry; Wilkinson, G., Ed.; Pergamon: Oxford, 1982; Vol. 2, p 519.
2. (a) Yamamoto, Y. ACR 1987, 20, 243. (b) Yamamoto, Y.; Saito, Y.; Maruyama, K. JOM 1985, 292, 311. (c) Koreeda, M.; Tanaka, Y. TL 1987, 28, 143. (d) Keck, G. E.; Abbott, D. E.; Wiley, M. R. TL 1987, 28, 139. (e) Yamamoto, Y.; Kobayashi, K.; Okano, H.; Kadota, I. JOC 1992, 57, 7003.
3. Nishiyama, H.; Sakuta, K.; Itoh, K. TL 1984, 25, 2487.
4. (a) Yamamoto, Y.; Hatsuya, S.; Yamada, J. JOC 1990, 55, 3118. (b) Yamamoto, Y.; Hatsuya, S.; Yamada, J. CC 1987, 561. (c) Yamamoto, Y.; Hatsuya, S.; Yamada, J. CC 1988, 86.
5. Kuivila, H. G. S 1970, 499.
6. Alleston, D. L.; Davies, A. G. JCS 1962, 2050.
7. Jones, K.; Lappert, M. F. JCS 1965, 1944.
8. Tanaka, M. TL 1980, 21, 2959.
9. Kricheldort, H. R.; Leppert, E. S 1976, 329.
10. Kocheshkov, K, A.; Nesmeyanov, A. N.; Puzyreva, V. P. CB 1936, 69, 1639.
11. Van der Kerk, G. J. M.; Luijten, J. G. A. J. Appl. Chem. 1956, 6, 49.
12. Tamborski, C.; Ford, F. E.; Soloski, E. J. JOC 1963, 28, 237.
13. (a) Sharma, S.; Oehlschlager, A. C. JOC 1989, 54, 5064. (b) Hibino, J.; Matsubara, S.; Morizawa, Y.; Oshima, K.; Nozaki, H. TL 1984, 25, 2151.
14. Still, W. C. JACS 1978, 100, 1481.
15. Piers, E.; Morton, H. E.; Chong, J. M. CJC 1987, 65, 78.
16. (a) Gill, M.; Bainton, H. P.; Rickards, R. W. TL 1981, 22, 1437. (b) Seitz, D. E.; Lee, S.-H. TL 1981, 22, 4909.
17. (a) Seyferth, D.; Weiner, M. A. JOC 1961, 26, 4797. (b) Grignon, J.; Servens, C.; Pereyre, M. JOM 1975, 96, 225.
18. (a) Yamada, J.; Asano, T.; Kadota, I.; Yamamoto, Y. JOC 1990, 55, 6066. (b) Kadota, I.; Gevorgyan, V.; Yamada, J.; Yamamoto, Y. SL 1991, 823. (c) Yamamoto, Y.; Yamada, J.; Kadota, I. TL 1991, 32, 7069. (d) Gevorgyan, V.; Kadota, I.; Yamamoto, Y. TL 1993, 34, 1313.
19. Obayashi, M.; Utimoto, K.; Nozaki, H. JOM 1979, 177, 145.
20. Groh, B. L. TL 1991, 32, 7647.
21. Fryzuk, M. D.; Bates, G. S.; Stone, C. TL 1986, 27, 1537.
22. Stille, J. K.; Simpson, J. H. JACS 1987, 109, 2138.
23. Yamamoto, Y.; Yatagai, H.; Maruyama, K. CC 1981, 162.

Isao Kadota & Yoshinori Yamamoto

Tohoku University, Sendai, Japan

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