[71504-26-2]  · C7H14Si  · (E)-1-Trimethylsilyl-1,3-butadiene  · (MW 126.30)

(diene for Diels-Alder reactions,2,3 creating allylsilanes that can be converted to a variety of functionalized cyclohexenes with a shift of the double bond from its original position in the cycloaddition;3 synthesis of a chiral allylborane;4 synthesis of allylsilanes5,6 and trienes7)

Physical Data: bp 110-115 °C, 70-74 °C/210 mmHg.

Solubility: freely sol all organic solvents.

Analysis of Reagent Purity: NMR: d (CDCl3) 6.6-4.9 (5H, m), 0.02 (9H, s).3 UV: lmax (EtOH) 231 nm (ε 22 000).2

Preparative Methods: prepared geometrically pure by Wittig2 or Peterson3 reactions on (E)-3-trimethylsilylpropenal,8 by pyrolysis of silylated 3-sulfolenes,9 and by coupling (E)-2-trimethylsilylvinyl bromide with Lithium Divinylcuprate.10 It can also be prepared geometrically impure, but largely (E), from Allyltrimethylsilane by a vinylogous Ramberg-Bäcklund reaction,11 and from 1,3-Butadienyl-1-magnesium Chloride and Chlorotrimethylsilane.4

Handling, Storage, and Precautions: reasonably stable in the absence of air and radical initiators. It should be kept in a stoppered flask or sealed ampule in the presence of hydroquinone. Its toxicity is unknown, but the presence of a trimethylsilyl group is generally benign.

Diels-Alder Reactions.

(E)-1-Trimethylsilyl-1,3-butadiene undergoes Diels-Alder reactions with the usual dienophiles, with unimpaired endo stereoselectivity, but at a somewhat slower rate than 1,3-butadiene itself (eq 1).2,3 The regioselectivity with unsymmetrical dienophiles is poor (eq 2).2,3 The adducts are allylsilanes, which react with electrophiles in the usual way (eqs 3 and 4) to give cyclohexenes with a double bond shifted from the original position.3

Because of the low level of regiocontrol imparted by the silyl group, other substituents on 1-silylated dienes can impart better regiocontrol (eq 5).3


The diene is used as a starting material for the synthesis of the chiral allylborane (1) or its enantiomer (eq 6).4


Reduction of the diene with Lithium and t-butanol in liquid ammonia gives Crotyltrimethylsilane,5 and reaction with Grignard reagents gives longer chain (E)-allylsilanes (eq 7).6

Triene Synthesis.

Like other vinylsilanes, 1-trimethylsilyl-1,3-butadiene can be used in a Hiyama coupling reaction with vinyl iodides (eq 8).7

1. Luh, T.-Y.; Wong, K.-T. S 1993, 349.
2. Jung, M. E.; Gaede, B. T 1979, 35, 621.
3. Carter, M. J.; Fleming, I.; Percival, A. JCS(P1) 1981, 2415.
4. Short, R. P; Masamune, S. JACS 1989, 111, 1892.
5. Koshutina, L. L.; Koshutin, V. I. ZOB 1978, 48, 932 (CA 1978, 89, 43 592z).
6. Koshutin, V. I.; ZOB 1978, 48, 1665 (CA 1978, 89, 163 645r).
7. Hatanaka, Y.; Hiyama, T. JOC 1988, 53, 918.
8. Jones, T. K.; Denmark, S. E. OSC 1990, 7, 524, and ref. 3.
9. (a) Bloch, R.; Abecassis, J. TL 1983, 24, 1247. (b) Chou, T.; Tso, H.-H.; Tao, Y.-T.; Lin, L. C. JOC 1987, 52, 244.
10. Koshutin, V. I.; Nazarenko, N. P. ZOB 1982, 52, 2376 (CA 1983, 98, 89 445t).
11. Block, E.; Aslam, M.; Eswarakrishnan, V.; Gebreyes, K.; Hutchinson, J.; Iyer, R.; Laffitte, J.-A.; Wall, A. JACS 1986, 108, 4568.

Ian Fleming

Cambridge University, UK

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