Stereoselective Epoxidation of Allylic Alcohols and Dehydrogenative Oxidation of Secondary Alcohols by Means of t -Butyl Hydroperoxide and Aluminium Reagents
1983; Oxford University Press; Volume: 56; Issue: 12 Linguagem: Inglês
10.1246/bcsj.56.3791
ISSN1348-0634
AutoresKazuhiko Takai, Koichiro Oshima, Hitosi Nozaki,
Tópico(s)Polyoxometalates: Synthesis and Applications
ResumoTreatment of a solution of geraniol and (t-BuO)3Al in benzene with t-BuOOH at 5 °C gives (2R*, 3R*)-2,3-epoxy-3,7-dimethyl-6-octenyl acetate in 83% yield after acetylative workup. Eight allylic alcohols are converted to α,β-epoxy alcohols in preparative yields. The epoxidation of secondary (E)-allylic alcohols shows opposite stereoselectivities to t-BuOOH–VO(acac)2 system. Asymmetric epoxidation with a chiral hydroxamic acid as a ligand gives unsatisfactory degrees of enantiomeric excess. The same system can also convert secondary alcohols into ketones in excellent yields, while primary ones react very slowly.
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