More than twenty examples illustrate the recently developed oxidoketone-alkynone-fragmentation, whereby α,β-epoxy-ketones are cleaved under mild conditions with p-toluenesulfonyl-hydrazine to give acetylenic ketones or aldehydes.
Experimental details concerning some examples of the tosylhydrazone version of the α, β-epoxyketone alkynone fragmentation as well as a discussion of this process are given.
Selektive Addition von gasf�rmigem Chlorwasserstoff an kristalline Epoxide und Steroid-Epoxide
作者:Gerd Kaupp、Anke Ulrich、Gerhard Sauer
DOI:10.1002/prac.19923340503
日期:——
Solid epoxides add gaseous HCl or HBr regioselectively and without melting, if the melting points are sufficiently high. Such additions proceed diastereoselectively with chiral epoxides. These gas/solid reactions are compared to similar transformations in solution. One observes interesting reaction sequences in the conversions of steroidal epoxides. Thus, the opening of the epoxide ring may be followed by cationic rearrangements, or it occurs elimination of water, if it creates conjugation to a carbonyl group.
Kerb,U. et al., Angewandte Chemie, 1968, vol. 80, # 21, p. 916