Simmons-Smith reaction

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The Simmons-Smith reaction is an organic reaction in which a carbenoid reacts with an alkene (or alkyne) to form a cyclopropane.^[1][2][3] Thus, cyclohexene, methylene iodide, and a zinc-copper couple (as (iodomethyl)zinc iodide, ICH₂ZnI) yield bicyclo[4.1.0]heptane.^[4][5]

Alternatively, diethylzinc is used instead of the zinc-copper couple.

The Simmons-Smith reaction is generally subject to steric effects, and thus cyclopropanation usually takes place on the less hindered face.^[6][7] However, when hydroxy substituents are present on chiral carbons, the zinc coordinates with the hydroxy substituents, directing cyclopropanation to the same face, which may or may not be sterically favorable ^[8]:

[edit] References

1. ↑  Simmons, H.E.; Smith, R.D. J. Am. Chem. Soc., 1958, 80, 5323.
2. ↑  Simmons, H.E.; Smith, R.D. J. Am. Chem. Soc., 1959, 81, 4256.
3. ↑  Denis, J.M.; Girard, J.M.; Conia, J.M. Synthesis, 1972, 549.
4. ↑  Smith, R. D.; Simmons, H. E. Organic Syntheses, Coll. Vol. 5, p.855 (1973); Vol. 41, p.72 (1961). (Article)
5. ↑  Ito, Y.; Fujii, S.; Nakatuska, M.; Kawamoto, F.; Saegusa, T. Organic Syntheses, Coll. Vol. 6, p.327 (1988); Vol. 59, p.113 (1979). (Article)
6. ↑  Simmons, H. E. et al. Org. React. 1973, 20, 1. (Review)
7. ↑  Girard, C.; Conia, J. M. J. Chem. Res. (S) 1978, 182. (Review)
8. ↑  Grieco et al. J. Org. Chem. 1977, 42, 4113.