Chlorotrimethylstannane

Me3SnCl

[1066-45-1]  · C3H9ClSn  · Chlorotrimethylstannane  · (MW 199.25)

(starting material for the synthesis of alkyl-, allyl-, alkenyl-, and alkynyltrimethylstannanes and trimethyltin enolates; palladium-catalyzed coupling reactions14)

Alternate Name: trimethyltin chloride.

Physical Data: mp 37-39 °C; bp 153-156 °C.

Solubility: sol ether, THF, hexane, CH2Cl2.

Form Supplied in: white solid; widely available.

Handling, Storage, and Precautions: is air stable, but is decomposed by moisture. Commercially available trimethyltin chloride may be used as received. The reagent is very toxic and corrosive, and should be handed with gloves in a fume hood.

Introduction.

Trimethyltin hydride, cyanide, methoxide, azide, and lithium are prepared from trimethyltin chloride by the procedures similar to those given in Tri-n-butylchlorostannane. Similarly, hexamethylditin, bis(trimethyltin) oxide, and diethylaminotrimethyltin are prepared from trimethyltin chloride.

Organotrimethyltins via Transmetalation.

Lithiated 1,3-dithianes react with trialkyltin or triphenyltin chlorides to form the corresponding 1,3-dithian-2-yltin compounds.1 The organocopper compound, derived from (a-(dialkoxyboryl)alkyl)zinc iodide and CuCN.2LiCl, reacts with trimethyltin chloride to afford the a-boron substituted organotin in 87% yield (eq 1).2 Accordingly, sulfur- and boron-stabilized anions are readily converted to the corresponding trimethyltin derivatives.

Allyl anions are also transformed to the corresponding allyltrimethyltin derivatives in high yields. Allyl anions substituted by 9-BBN, generated from B-Allyl-9-borabicyclo[3.3.1]nonane by treatment with Lithium 2,2,6,6-Tetramethylpiperidide (LTMP) react with trimethyltin chloride to afford the a-trimethyltin-substituted allyl-9-BBN in good yields (eq 2).3 Trimethyltin bromide may also be used in this procedure. The resulting allylic borane reacts with aldehydes in the presence of pyridine to produce the anti-homoallyl alcohols with a (Z)-alkenyltrimethylstannyl group (eq 3)4 (see also 9-[1-(Trimethylsilyl)-2(E)-butenyl]-9-borabicyclo[3.3.1]nonane). g-Chloro-substituted allyltrimethyltins are prepared by the reaction of trimethyltin chloride with chloro-substituted allyllithiums, which are generated from allyl chlorides and LTMP.5 2,4-Pentadienyltrimethylstannane, prepared by the reaction of pentadienyllithium with trimethyltin chloride, reacts with p-quinones in the presence of BF3.OEt2 to afford the corresponding pentadienylated conjugate adducts in fair to good yields without formation of the Diels-Alder adduct (eq 4).6 On the other hand, the use of 2,4-pentadienyltrimethylsilane produces the Diels-Alder adduct exclusively. The tin reagent produces the conjugate adducts with p-quinones, regardless of the substituents and their substitution pattern. With a,b-unsaturated aldehydes, the pentadienyl tin reagent gives the 1,2-adducts (pentadienyl carbinols), whereas the 1,4-adduct is obtained with chalcone.6 Here also, the reaction of pentadienyltrimethylsilane with crotonaldehyde affords the corresponding Diels-Alder adduct.7

The intramolecular transfer reaction of lithium 1-alkynyltrialkylborates, prepared in situ from lithium acetylides and trialkylboranes, induced by trimethyltin chloride is highly stereoselective, with the resultant dialkylboryl-substituted alkenylstannanes having the migrating alkyl group trans to the trialkyltin group (eq 5).8 Conversion of the resulting dialkylboryl group (R = Et) to the alkenylcopper followed by treatment with methanol or alkyl halides produces di- or trisubstituted alkenyltrimethylstannanes, respectively (eq 6).9 By starting from conjugated terminal enynes, 2-(trimethylstannyl)-1,3-butadienes are similarly synthesized.

Alkenylstannanes have been utilized for a variety of synthetic applications. The palladium-catalyzed coupling reaction of vinyl triflates and vinyl halides with alkenylstannanes affords 1,3-dienes.10 The facile transmetalation reaction between alkenylstannanes and alkyllithiums remains as one of the most direct routes to certain alkenyllithium reagents. Treatment of alkenylstannanes with iodine affords the corresponding vinyl iodides with retention of configuration of the vinyl group.

Although the hydrostannylation reaction of alkynes provides a simple route to alkenylstannanes, it is generally not stereoselective. The addition reaction of (trialkylstannyl)copper and related reagents to 1-alkynes and a,b-alkynic esters and amides exhibits high regio- and stereoselectivity.11 Vinyl triflates and vinyl iodides have also been converted to alkenylstannanes by the reaction with Me3SnMgMe in the presence of Copper(I) Cyanide catalyst.11b The hydroalumination of alkynes with Diisobutylaluminum Hydride followed by treatment with Methyllithium yields alanates, which are converted to alkenyltrimethylstannanes by addition of trimethyltin chloride (see also Tri-n-butylchlorostannane).12 Generally, conversion of vinylalanes to alanates (ate complexes) is needed to enhance the reactivity toward electrophiles such as Me3SnCl. The direct transmetalation of vinylalanes to vinylstannanes is accomplished by carrying out the reaction with Me3SnCl in the presence of LiX (X = Cl, Br, I) in DME.13

Palladium-Catalyzed Reactions.

Benzylchlorobis(triphenylphosphine)palladium(II) catalyzes the reaction of acid chlorides with tetraorganotin compounds (Me4Sn, Ph4Sn, Ph3SnMe, Me3SnCH2Ph, (PhCH2)4Sn, Bu4Sn, Bu3SnCH=CH2, Me3SnCl) to give ketones in quantitative yields (eq 7).14 Trimethyltin chloride (1 equiv) also reacts with benzoyl chloride to give acetophenone in quantitative yield, although the reaction takes five times longer to reach completion than the reaction using Tetramethylstannane. By using a trimethyl- or tributylorganotin reagent, the group other than the methyl or butyl groups transfers exclusively in the following order: RC&tbond;C > RCH=CH > aryl > RCH=CHCH2 &AApprox; arylCH2 > MeOCH2.

The palladium-catalyzed coupling of alkenyl iodides with alkynyltrimethylstannanes takes place under mild conditions, stereospecifically and chemoselectively, to give high yields of conjugated enynes (eq 8).15 Organic groups on tin undergo selective transmetalation with palladium, as shown above, and the alkynic group has the fastest transfer rate of all the organic substituents.

Trimethyltin Enolates.

Trimethyltin enolates, prepared in situ from lithium enolates and trimethyltin chloride, undergo a rapid aldol condensation with aldehydes to give nearly a 1:1 mixture of the syn and anti aldols in high yields.16 However, the trimethyltin enolate generated in situ from the lithium enolate of 4-thianone gives the anti aldol with very high diastereoselectivity upon treatment with 2-methylpropanal (eq 9).17 The lithium enolate itself also provides high anti diastereoselectivity (95:5) in this case.


1. Klaveness, J.; Rise, F.; Undheim, K. JOM 1986, 303, 189.
2. Knochel, P. JACS 1990, 112, 7431.
3. Yatagai, H.; Yamamoto, Y.; Maruyama, K. JACS 1980, 102, 4548.
4. Yamamoto, Y.; Yatagai, H.; Maruyama, K. JACS 1981, 103, 3229.
5. Hosomi, A.; Kohra, S.; Tominaga, Y.; Ando, M.; Sakurai, H. CPB 1987, 35, 3058.
6. Naruta, Y.; Nagai, N.; Arita, Y.; Maruyama, K. CL 1983, 1683.
7. Seyferth, D.; Pornet, J.; Weinstein, R. M. OM 1982, 1, 1651. Hosomi, A.; Saito, M.; Sakurai, H. TL 1980, 21, 3783.
8. Hooz, J.; Mortimer, R. TL 1976, 805.
9. Wang, K. K.; Chu, K.-H.; Lin, Y.; Chen, J.-H. T 1989, 45, 1105.
10. Scott, W. J.; Stille, J. K. JACS 1986, 108, 3033.
11. (a) Westmijze, H.; Ruitenberg, K.; Meijer, J.; Vermeer, P. TL 1982, 23, 2797. (b) Matsubara, S.; Hibino, J.; Morizawa, Y.; Oshima, K.; Nozaki, H. JOM 1985, 285, 163. (c) Piers, E.; Chong, J. M. JOC 1982, 47, 1602. (d) Piers, E.; Chong, J. M. CC 1983, 934. (e) Chenard, B. L.; Van Zyl, C. M.; Sanderson, D. R. TL 1986, 27, 2801.
12. Groh, B. L.; Kreager, A. F.; Schneider, J. B. SC 1991, 21, 2065.
13. Groh, B. L. TL 1991, 32, 7647.
14. Milstein, D.; Stille, J. K. JOC 1979, 44, 1613. Stille, J. K. AG(E) 1986, 25, 508.
15. Stille, J. K.; Simpson, J. H. JACS 1987, 109, 2138.
16. Yamamoto, Y.; Yatagai, H.; Maruyama, K. CC 1981, 162.
17. Hayashi, T. TL 1991, 32, 5369.

Yoshinori Yamamoto

Tohoku University, Sendai, Japan



Copyright 1995-2000 by John Wiley & Sons, Ltd. All rights reserved.