[66222-29-5]  · C13H29ISn  · Tri-n-butyl(iodomethyl)stannane  · (MW 431.03)

(preparation of (a-heteroalkyl)stannanes for subsequent tin-lithium exchange1 or [2,3]-Wittig rearrangement;2 preparation of (tri-n-butylstannyl)methyllithium3)

Alternate Name: tributyl(iodomethyl)tin.

Physical Data: colorless liquid; bp 100-110 °C/0.01 mmHg.

Preparative Methods: prepared by treatment of Iodomethylzinc Iodide with Tri-n-butylchlorostannane,4 or by reaction of tri-n-butyl(chloromethyl)tin with NaI.5

Handling, Storage, and Precautions: potentially toxic; should be handled in a well ventilated hood.

General Discussion.

Tri-n-butyl(iodomethyl)tin (1) has been used extensively as an electrophile in the preparation of a-heteroalkylstannanes such as tri-n-butylstannylmethyl ethers,2 N-acylated a-aminostannanes,1 and S-stannylmethyl phosphinothioates.6 Tri-n-butylstannylmethyl ethers of allylic alcohols undergo tin-lithium exchange and [2,3]-sigmatropic rearrangement upon treatment with n-Butyllithium. For example, the stannylated ether (2) provides the homoallylic alcohol (3) with nearly exclusively the (Z) configuration (eq 1).2

Diastereoselective [2,3]-Wittig rearrangements of this type have been reported.7 This reaction sequence has been applied to the synthesis of alkene dipeptide isosteres,8 as well as a number of natural products including (-)-punctatin A (eq 2).9 The homoallylic (tri-n-butylstannyl)methyl ether (4) undergoes stereoselective anionic cyclization to the cis-2,4-disubstituted tetrahydrofuran (5) upon transmetalation with n-BuLi (eq 3).10 Tin-lithium exchange of the oxazolidinone-derived a-aminostannane (6) generates nitrogen-substituted organolithium compounds which react with a variety of electrophiles (eq 4).1

Tri-n-butyl(iodomethyl)tin is a useful reagent for the preparation of alkenes from sulfides,11 sulfones,12 and nitriles.13 The moderately hindered sulfone (7) is converted to the corresponding exocyclic alkene by fluoride-induced desulfonylstannylation of (8) (eq 5).14 Tri-n-butyl(iodomethyl)tin has also been used to prepare (tri-n-butylstannyl)methyllithium (9), which reacts with electrophiles as a methylene double anion equivalent.15 For example, transmetalation of (1) using n-BuLi followed by addition of an ester generates the corresponding ketone enolate which may participate in aldol reactions (eq 6).

1. Pearson, W. H.; Lindbeck, A. C.; Kampf, J. W. JACS 1993, 115, 2622.
2. Still, W. C.; Mitra, A. JACS 1978, 100, 1927.
3. Kauffmann, T.; Kriegesmann, R.; Altepeter, B.; Steinseifer, F. CB 1982, 115, 1810.
4. Still, W. C. JACS 1978, 100, 1481.
5. Seitz, D. E.; Carroll, J. J.; Cartaya, C. P.; Lee, S.; Zapata, A. SC 1983, 13, 129.
6. Kawashima, T.; Kojima, S.; Miyake, T.; Inamoto, N. TL 1989, 30, 201.
7. Balestra, M.; Kallmerten, J. TL 1988, 29, 6901.
8. Bol, K. M.; Liskamp, R. M. J. T 1992, 48, 6425.
9. Paquette, L. A.; Sugimura, T. JACS 1986, 108, 3841.
10. Broka, C. A.; Lee, W. J.; Shen, T. JOC 1988, 53, 1336.
11. Ochiai, M.; Tada, S.; Sumi, K.; Fujita, E. TL 1982, 23, 2205.
12. Ochiai, M.; Sumi, K.; Fujita, E.; Tada, S. CPB 1984, 32, 1829.
13. Pearlman, B. A.; Putt, S. R.; Fleming, J. A. JOC 1985, 50, 3625.
14. Pearlman, B. A.; Putt, S. R.; Fleming, J. A. JOC 1985, 50, 3622.
15. Sato, T.; Matsuoka, H.; Igarashi, T.; Minomura, M.; Murayama, E. JOC 1988, 53, 1207.

Steven K. Davidsen

Abbott Laboratories, Abbott Park, IL, USA

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