Highly stereoselective metal-catalyzed epoxidation of hydroxy vinyl sulfones ¹

Abstract

Acyclic α-hydroxyalkyl α,β-unsaturated sulfoxides undergo oxidation at sulfur followed by a highly regio- and stereoselective epoxidation at the electron deficient alkene by treatment with Bu^tOOH–VO(acac)₂; this methodology allows for an expedient entry into unusual carbohydrate fragments.

References

1. Taken in part from the M. S. Theses of P. M. and J. P.
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8. The structure of 4c was assigned by comparison of its spectral data with those of very closely related compounds described by Jackson in a thorough study of the nucleophilic epoxidation of hydroxy vinyl sulfones. See: R. F. W. Jackson, S. P. Standen, W. Clegg and A. McCamley, J. Chem. Soc., Perkin Trans. 1, 1995, 141.
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10. The stereochemistry of the newly created center is tentatively assigned in analogy with the results of Procter for nucleophilic additions to α,β-epoxy aldehydes. See: G. P. Howe, S. Wang and G. Procter, Tetrahedron Lett., 1987, 28, 2629 For a leading reference on reagent controlled allylation of α,β-epoxy aldehydes, see: W. R. Roush, J. A. Straub and M. S. VanNieuwenhze, J. Org. Chem., 1991, 56, 1636.
11. The standard catalytic dihydroxylation of our vinyl oxiranes takes place with an unexpectedly high level of selectivity; these results will be published elsewhere. For leading references on dihydroxylation of vinyl oxiranes, see: (a) J. V. Allen, S. Bergeron, M. J. GriYths, S. Mukherjee, S. M. Roberts, N. M. Williamson and L. E. Wu, J. Chem. Soc., Perkin Trans. 1, 1998, 3171; (b) N.-S. Kim, J.-R. Choi and J. K. Cha, J. Org. Chem., 1993, 58, 7096.