Highly Regio- and Enantioselective Monoepoxidation of Conjugated Dienes
1998; American Chemical Society; Volume: 63; Issue: 9 Linguagem: Inglês
10.1021/jo9721195
ISSN1520-6904
AutoresMichael Frohn, Molly Dalkiewicz, Yong Qiang Tu, Zhixian Wang, Yian Shi,
Tópico(s)Organic Chemistry Cycloaddition Reactions
ResumoThis paper describes a highly effective and mild asymmetric monoepoxidation method for conjugated dienes using a fructose-derived chiral ketone 1 as catalyst and Oxone as oxidant. The regioselectivies and enantioslectivies are very high in most cases. For unsymmetrical dienes, the regioselectivity can be regulated by using steric and electronic control. The olefin substrates include trans-disubstituted and trisubstituted olefins that can bear a wide range of functional groups such as hydroxyl groups, TBS ethers, or esters. The enantiomeric excesses for the major monoepoxides range from 89% to 97%. The epoxidation is believed to proceed via a spiro mode.
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