Ketone homologation to produce α-methoxyketones: application to conduritol synthesis

Abstract

The scope of Trost’s sulfone homologation procedure for the conversion of ketones into their α-methoxylated higher homologues has been dramatically expanded. The use of zirconium (or hafnium) tetrachloride in the hydroxy sulfone rearrangement step gives good yields with the adducts of aryl alkyl ketones, dialkyl ketones and cycloalkanones, and the rearrangement occurs with total regioselectivity. Mechanistic observations are presented which account for the formation of α-hydroxy aldehydes as by-products and which indicate an efficient method for their preparation. Application of the homologation methodology to the stereoselective synthesis of dihydroconduritols is described.

References

1. For reviews see P. M. Wovkulich, Section 3.3 in Comprehensive Organic Synthesis, vol. 1, eds. B. M. Trost and I. Fleming, Pergamon, Oxford, 1991; M. Hesse, Ring Enlargement in Organic Chemistry, VCH, New York, 1991; C. D. Gutsche and D. Redmore, Carbocyclic Ring Expansion Reactions, Academic Press, London, 1968.
2. For recent advances see A. R. Katritzky, L. Xie, D. Toader and L. Serdyuk, J. Am. Chem. Soc., 1995, 117, 12 015 and references therein.
3. B. M. Trost and G. K. Mikhail, J. Am. Chem. Soc., 1987, 109, 4124.
4. H. Finch, A. M. M. Mjalli, J. G. Montana, S. M. Roberts and R. J. K. Taylor, Tetrahedron, 1990, 46, 4925.
5. M. Azadi Ardakani, G. C. Loftus, A. M. M. Mjalli, R. F. Newton and S. M. Roberts, J. Chem. Soc., Chem. Commun., 1989, 1709.
6. Preliminary communication: J. G. Montana, N. Phillipson and R. J. K. Taylor, J. Chem. Soc., Chem. Commun., 1994, 2289.
7. S. Shimada, Y. Hashimoto and K. Saigo, J. Org. Chem., 1993, 58, 5226 for more recent applications of zirconium tetrafluoride see D. C. Harrowven and R. F. Dainty, Tetrahedron Lett., 1996, 37, 3607 and 7659.
8. B. Rickborn, Section 3.2 in Comprehensive Organic Synthesis, vol. 3, eds. B. M. Trost and I. Fleming, Pergamon, Oxford, 1991.
9. S. Knapp, A. F. Trope, M. S. Theodore, N. Hirata and J. J. Barchi, J. Org. Chem., 1984, 49, 608; R. J. Israel and R. K. Murray, Jr., J. Org. Chem., 1985, 50, 1573.
10. D. Enders and U. Reinhold, Synlett, 1994, 792; M. Hayashi, T. Yoshiga, K. Nakatani, K. Ono and N. Oguni, Tetrahedron, 1994, 50, 2821.
11. (a) A. Barco, G. de Giuli and G. P. Pollini, Synthesis, 1972, 626; (b) see also B. C. McKusic, J. Am. Chem. Soc., 1948, 70, 1976.
12. N. Chida, T. Tobe and S. Ogawa, Tetrahedron Lett., 1994, 35, 7251.
13. D. R. Borcherding, S. A. Scholtz and R. T. Borchardt, J. Org. Chem., 1987, 52, 5457 see also C. L. Mariën, E. L. Esmans, F. Lemière and R. A. Dommisse, Synth. Commun., 1997, 27, 205; C. R. Johnson, J. L. Esker and M. C. van Zandt, J. Org. Chem., 1994, 59, 5854.
14. D. Beer, R. Meuwly and A. Vasella, Helv. Chim. Acta, 1982, 65, 2570.
15. S. D. Géro, Tetrahedron Lett., 1966, 591.
16. L. Pingli and M. Vandewalle, Tetrahedron, 1994, 50, 7061; C. Le Drian, E. Vieira and P. Vogel, Helv. Chim. Acta, 1989, 72, 338.
17. B. M. Trost and C. H. Miller, J. Am. Chem. Soc., 1975, 97, 7182.
18. K. Schank and H.-G. Scmitt, Chem. Ber., 1977, 110, 3235.
19. H. R. Sonawane, B. S. Nanjundiah, D. G. Kulkarni and J. R. Ahuja, Tetrahedron, 1988, 44, 7319.
20. G. A. Russell, D. F. Lawson, H. C. Malkus, R. D. Stephens, G. R. Underwood, T. Takano and V. Malatesta, J. Am. Chem. Soc., 1974, 96, 5830.
21. This compound has been described several times in the literature (most recently by E. Hata, T. Takai, T. Yamada and Y. Mukaiyama, Chem. Lett., 1994, 535), but no data has been published previously..
22. J. E. McMurray and J. Melton, J. Org. Chem., 1973, 38, 4367.