Asymmetric Desymmetrization of Prochiral 1,3-Diols via Diastereoselective C-O Bond Fission of Bicyclic Acetal Using a Chiral Sulfoxide as a Chiral Auxiliary

摘要

Asymmetric desymmetrization of a prochiral 1,3-dioI was established by diastereoselective C-O bond fission of the chiral a-sulfinyl aeetal 6. Treatment of 6 with titanium tetrachloride afforded mainly 7a via an oxonium intermediate, while with lithium diisopropylamide 7b was selectively obtained via diastereoselective B-elimination followed by an olefin isomerization.