Danheiser annulation

What is Danheiser annulation?

The Danheiser annulation, which involves the synthesis of five-membered carbocycles and heterocycles (including dihydrofurans, pyrrolines, isoxazoles, azulenes, and furans) from organosilanes and electron-deficient compounds via a [3+2] annulation, was initially reported by Danheiser et. al. in 1981. In this reaction, organosilanes serve as three-carbon components (such as allenylsilanes, propargylsilanes, and allylsilanes), while electron-deficient compounds (such as α,β-unsaturated compounds) act as the other two-carbon components.

Danheiser annulation
Danheiser annulation

It is worth noting that the Danheiser annulation can be facilitated by strong Lewis acids such as TiCl4. Furthermore, the use of allylsilane and propargylsilanes as a three-carbon component source can be optimized by incorporating a large trialkylsilyl group, which can promote the annulation and suppress the normal desilylation, resulting in the formation of allenes. Additionally, the Danheiser annulation has been found to occur in allylstannanes.

References

  • Danheiser, R. L.; Carini, D. J. and Basak, A., J. Am. Chem. Soc., 1981, 103, 1604
  • Danheiser, R. L.; Fink, D. M. and Tsai, Y.-M., Org. Synth. Coll. Vol. VIII, 1993, 347
  • Danheiser, R. L. and Fink, D. M., Tetrahedron Lett., 1985, 26, 2513
  • Danheiser, R. L.; Carini, D. J.; Fink, D. M. and Basak, A., Tetrahedron, 1983, 39, 935
  • Danheiser, R. L.; Kwasigroch, C. A. and Tsai, Y.-M., J. Am. Chem. Soc., 1985, 107, 7233
  • Danheiser, R. L. and Becker, D. A., Heterocycles, 1987, 25, 277
  • Becker, D. A. and Danheiser, R. L., J. Am. Chem. Soc., 1989, 111, 389
  • Danheiser, R. L.; Stoner, E. J.; Koyama, H.; Yamashita, D. S. and Klade, C. A., J. Am. Chem. Soc., 1989, 111, 4407
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