The Katsuki-Sharpless asymmetric epoxidation of (E)-2,5-dihydroxy-2,5-dimethyl-3-hexene
摘要:
The first asymmetric epoxidation of a tertiary allylic alcohol by the Katsuki-Sharpless reaction has been demonstrated using (E)-2,5-dihydroxy-2,5-dimethyl-3-hexene as a tertiary allylic alcohol substrate to afford optically active 3,4-epoxy-2,5-dihydroxy-2,5-dimethylhexane in 70% ee in an excellent chemical yield.
Hydrogen Bond Catalyzed Enantioselective Vinylogous Mukaiyama Aldol Reaction
作者:Vijaya Bhasker Gondi、Michel Gravel、Viresh H. Rawal
DOI:10.1021/ol052301p
日期:2005.12.1
[chemical reaction: see text]. The concept of hydrogen bonding catalysis was extended to the vinylogous Mukaiyamaaldolreaction, which gives rapid access to polyketide derivatives. The reaction of the silyldienol ether shown and a range of aldehydes catalyzed by TADDOL proceeds regiospecifically to produce the addition products in good yields and enantiomeric excesses.