[1118-46-3]  · C4H9Cl3Sn  · n-Butyltrichlorostannane  · (MW 282.16)

(Lewis acid catalyst for polymerization reactions, esterifications,2 dehydration processes, acetalizations, and transacetalizations3)

Alternate Names: butyltrichlorotin; butyltin trichloride.

Physical Data: bp 93 °C/10 mmHg; d 1.7 g cm-3; nD 1.5235.

Solubility: sol cold water, common organic solvents.

Form Supplied in: colorless liquid, widely available. Drying: the usual procedure is vacuum distillation. It dissolves in water to give strongly acidic, clear solutions. Hydrolysis is reversible: BuSnCl3 may be recovered by distillation.4

Handling, Storage, and Precautions: storage of anhydrous BuSnCl3 in a dark desiccator is recommended. It is reputed to be of low toxicity with respect to other organotins. Use in a fume hood.

Esterifications and Transesterifications.

Monoorganotin(IV) halides have been employed as esterification and transesterification catalysts.1e BuSnCl3 shows fairly good activity in the reactions shown in eqs 1 and 2.1e,2 BuSnCl3 is also an effective esterification catalyst for fatty acids derived from palm oil.2

Formation of Diallyl Ethers from Allylic Alcohols.

Butyltrichlorostannane catalyzes the dehydration of the following alcohols: (E,Z)-MeCH=CHCH2OH, (E)-MeCH=CHCH(OH)Me, Me2C=CHCH2OH, MeCH=CHCH(OH)CH2CH=CH2, and MeCH=CHCH(OH)CH(R)CH=CH2 (R = Me, n-Pr) to give isomeric mixtures of diallyl ethers5a in high yields (80-90%). Three isomeric species are formed from dehydration of (E)-3-penten-2-ol (eq 3).

Formation of Cyclic Ethers from Diols and Triols.

Organotin halides catalyze the conversion of 1,n-diols (n = 4-6) to cyclic ethers5 (eq 4); cyclizations of triols have been also described.3,5b

The catalytic activity of tin compounds is in the order MeSnCl3 &egt; PhSnCl3 &egt; SnCl4 > BuSnCl3 >> Me2SnCl2 > Bu2SnCl2 >> (Bu2SnCl)2O. BuSnCl3 is preferred over Tin(IV) Chloride and other monoorganotin halides because it is easy to handle, is inexpensive, and it can be recovered unchanged after workup. The following cyclic ethers have been synthesized from the corresponding diols: THF, 2-methyl-THF, 2,5-dimethyl-THF, 2,5-dihydrofuran, THP, 2-methyl-THP, 2,4-diallyl-THP, and 1,4-dioxane. 3-Hydroxy-THF and 3-hydroxymethyl-THP are also prepared in 92% and 70% yield from 1,3,4-trihydroxybutane and 1,5,6-trihydroxyhexane.3 A related cyclization is that of acetonylacetone to 2,5-dimethylfuran (eq 5).5b

Dehydration of Cyclic Diols.

1,3-Cyclopentane-, 1,4-cyclohexane-, and 1,2-cyclooctanediol, when heated at 180-235 °C in the presence of BuSnCl3 ([diol]/[Sn] in the range 20-40), give rise to mixtures of dehydrated products.5b 1,2-Cyclooctanediol yields a mixture of cyclooctanone, 1,4-epoxycyclooctane, and 1,3-cyclooctadiene (eq 6).5

Acetalizations and Transacetalizations of Diols and Triols.

BuSnCl3, which is able to act both as an acid and as a dehydrating agent, promotes acetalizations using diols and triols6 with many advantages compared to other methods. Reactions occur under mild conditions, with very short reaction times and in absence of solvent. Even aqueous solutions of aldehydes can be used (eq 7).

Transacetalizations of aldehyde dialkyl acetals, R1CH(OR2)2, with diols and polyols can be carried out using BuSnCl3 as the catalyst.6b,c As in acetalizations, reactions of glycerol with acetals provide mixtures of 1,3-dioxolanes and 1,3-dioxanes, the latter being the major products (eq 8).

Several examples where BuSnCl3 has been used as a catalyst for transacetalizations of 1,2-diols, 1,3-diols, 1,3-propanethiol, and 1,2,3-propane- and 1,2,4-butanetriols with 2,2-Dimethoxypropane have been reported.6d The same catalyst has been employed for acetonation of the above alcohols using the enol ether 2-Methoxypropene.6d

1. (a) Noltes, J. G.; Van der Kerk, G. J. M. Functionally Substituted Organotin Compounds; Tin Research Institute: Greenford, 1958. (b) Luijten, J. G. A.; Van der Kerk, G. J. M. Investigations in the Field of Organotin Chemistry; Tin Research Institute: Greenford, 1975. (c) Schumann, H.; Schumann, I. In Gmelin Handbook of Inorganic Chemistry, Organotin Compounds, Part. 6, Diorganotin Dichlorides, Organotin Trichlorides; Springer: Berlin, 1979. (d) Blunden, S. J.; Cusack, P. A.; Hill, R. The Industrial Uses of Tin Chemicals; RSC: London, 1985. (e) Harrison, P. G. The Chemistry of Tin; Chapman & Hall: New York, 1989.
2. Hobbs, L. A.; Smith, P. J. Adv. Organomet. Chem. 1992, 6, 95.
3. Tagliavini, G. JOM 1992, 437, 15.
4. Luijten, J. G. A. RTC 1966, 85, 873.
5. (a) Tagliavini, G.; Marton, D.; Furlani, D. T 1989, 45, 1187. (b) Marton, D.; Slaviero, P.; Tagliavini, G. T 1989, 45, 7099.
6. (a) Marton, D.; Slaviero, P.; Tagliavini, G. G 1989, 119, 359. (b) Marton, D.; Tagliavini, G. Main Group Met. Chem 1990, 13, 363. (c) Marton, D.; Slaviero, P.; Tagliavini, G.; Vanzan, N.; Zordan, M. Chemistry and Technology of Silicon and Tin; Kumar Das, V. G., Ed.; Oxford University Press: Oxford, 1992; p 277. (d) Carifiglio, T.; Marton, D; Stivanello, D..; Tagliavini, G. Main Group Met. Chem. 1992, 15, 247.

Giuseppe Tagliavini

University of Padua, Italy

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