566-31-4Relevant articles and documents
Reactions of steroidal 5,6-epoxides and cyclohexene oxide with aluminum alkoxides
Holland, Herbert L.,Khan, Saeed R.
, p. 2763 - 2768 (2007/10/02)
The isomeric 5,6α- and 5,6β-epoxycholestanes, in addition to an analogous series of compounds substituted at C-3 with hydroxy (α or β stereochemistry) or ethylene ketal groups, have been treated with aluminum isopropoxide or tert-butoxide.The latter series of reactions did not give identifiable material, but aluminum isopropoxide gave products derived from epoxide opening and rearrangement in all cases.With epoxides unsubstituted at C-3, aluminum isopropoxide functioned as a Lewis acid in promoting epoxide rearrangements.In the presence of a C-3 alcohol function, additional products were obtained arising from fragmentation of the C-4,C-5 bond, or from β-elimination of the epoxide involving the loss of a C-7 hydrogen.Meerwein-Pondorff reduction of product carbonyl groups was also observed.C-3 ketal substituted epoxides were rearranged cleanly to 6-hydroxy-Δ4-3-ketones.Cyclohexene oxide reacted with aluminum isopropoxide (but not with tert-butoxide) to give two products arising from epoxide addition reactions.Structures for these products are proposed based on their 13C nmr spectra, and a possible route for their formation is presented.None of the epoxides examined in this study reacted with magnesium methoxide.
