View PDF Version
 
DOI: 10.1039/A708188J (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1998, 463-466

13C NMR study on magnesium carbenoids

(Note: The full text of this document is currently only available in the PDF Version )

Volker Schulze, Ralf Löwe, Stefan Fau and Reinhard W. Hoffmann

Abstract

13C NMR chemical shifts suggest that α-iodoalkylmagnesium compounds have a carbenoid character in between that of α-haloalkyllithium and the corresponding zinc compounds.

References

  1. G. L. Closs and R. A. Moss, J. Am. Chem. Soc., 1964, 86, 4042 CrossRef CAS.
  2. G. Köbrich, Angew. Chem., 1967, 79, 15; Angew. Chem., Int. Ed. Engl., 1967, 6, 41 Search PubMed.
  3. (a) K. G. Taylor, Tetrahedron, 1982, 38, 2751 CrossRef; (b) H. Siegel, Top. Curr. Chem., 1982, 106, 55 CAS.
  4. D. Seebach, H. Siegel, J. Gabriel and R. Hässig, Helv. Chim. Acta, 1980, 63, 2046 CAS.
  5. D. Seebach, R. Hässig and J. Gabriel, Helv. Chim. Acta, 1983, 66, 308 CAS.
  6. S. E. Denmark, J. P. Edwards and S. R. Wilson, J. Am. Chem. Soc., 1992, 114, 2592 CrossRef CAS.
  7. S. E. Denmark and J. P. Edwards, J. Org. Chem., 1991, 56, 6974 CrossRef CAS.
  8. A. B. Charette and J.-F. Marcoux, J. Am. Chem. Soc., 1996, 118, 4539 CrossRef CAS.
  9. S. E. Denmark and S. P. O'Connor, J. Org. Chem., 1997, 62, 3390 CrossRef CAS.
  10. H. E. Simmons, T. L. Cairns, S. A. Vladuchick and C. M. Hoiness, Org. React. (NY), 1973, 20, 1 CAS.
  11. J. Villiéras, Bull. Soc. Chim. Fr., 1967, 1520 CAS; J. Villiéras, Organomet. Chem. Rev., Sect. A, 1971, 7, 81 Search PubMed.
  12. C. Prévost, Bull. Soc. Chim. Fr., 1931, 1372 CAS.
  13. D. Seyferth, R. L. Lambert, Jr. and E. M. Hanson, J. Organomet. Chem., 1970, 24, 647 CrossRef CAS.
  14. (a) R. C. Hahn and J. Tompkins, Tetrahedron Lett., 1990, 31, 937 CrossRef CAS; (b) C. DeLima, M. Julia and J.-N. Verpeaux, Synlett., 1992, 133 CrossRef CAS.
  15. A. Maercker, Angew. Chem., 1993, 105, 1072 CAS; Angew. Chem., Int. Ed. Engl., 1993, 32, 1032 Search PubMed.
  16. Zinc carbenoids undergo cyclopropanation reactions in refluxing diethyl ether;17 they have a minute tendency to insert intramolecularly into carbon–hydrogen bonds;18 they undergo nucleophilic attack by butyllithium at low temperatures.19 Magnesium carbenoids readily react at ca.–30 °C with external Grignard reagents;11,14,20 they undergo intramolecular cyclopropanation and CH-insertion reactions at –78 °C.21.
  17. E. P. Blanchard and H. E. Simmons, J. Am. Chem. Soc., 1964, 86, 1337 CrossRef CAS.
  18. R. C. Neumann, Jr., Tetrahedron Lett., 1964, 2541 CrossRef.
  19. See for example: T. Harada, T. Katsuhira, K. Hattori and A. Oku, J. Org. Chem., 1993, 58, 2958 Search PubMed.
  20. J. Villiéras, Bull. Soc. Chim. Fr., 1967, 1511 CAS.
  21. H. C. Stiasny, unpublished results from our laboratory.
  22. A. Müller, M. Marsch, K. Harms, J. C. W. Lohrenz and G. Boche, Angew. Chem., 1996, 108, 1639; Angew. Chem., Int. Ed. Engl., 1996, 35, 1518 Search PubMed.
  23. The geometry has been optimized at the MP2(full) level with GAUSSIAN94 Revision C.2 (Gaussian Inc. Pittsburgh, PA 1995) using a valence-double-zeta basis set augmented with one set of d-polarization functions for the non-hydrogen atoms [6-31G(d) for H, C, O, Mg and MWB-31G(d) for Cl and Br]26 plus d-polarization functions from Gaussian Basis Sets for Molecular Orbital Calculations, S. Huzinaga, ed., Elsevier, Amsterdam, 1984. The calculation of the harmonic infrared frequencies showed that the structure is a minimum on the potential energy surface Search PubMed.
  24. W. Hörner, T. S. Ertel, U. Kolb, H. Bertagnolli, R. W. Hoffmann, V. Schulze and G. van Dorsen, Daresbury Annual Reports, 1994–1995, 412 Search PubMed.
  25. (a) G. A. Olah, Top. Curr. Chem., 1979, 80, 19 CAS; (b) T. Laube, Angew. Chem., 1986, 98, 368 CAS; Angew. Chem., Int. Ed. Engl., 1986, 25, 349 Search PubMed.
  26. A. Bergner, M. Dolg, W. Küchle, H. Stoll and H. Preuss, Mol. Phys., 1993, 80, 1431 CAS.
Click here to see how this site uses Cookies. View our privacy policy here.