Unexpected Selectivity between Pinacolic Rearrangement and Intramolecular Displacement in the Acid-Promoted Epoxide Ring-Opening of 6-Exo-Cyano-3,8-Dioxabicyclo[18.104.22.168(2,4)]Oct-6-Endo-Yl Esters
Acid promoted epoxide ring opening of 2-exo-cyano-5-exo,6-exo-epohy-7-oxa-bicyclo[2.2.1]hept-2-endo-yl acetate is accompanied by a Wagnet-Meerwein (pinacolic) rearrangemant when run in CH2Cl2/HSO3-F and by endo acetoxy group participation when run in CF3CH(OH)CF3/HClO4. An efficient and stereoselective trans-double hydroxylation of centers C(5) and C(6) of the ''naked sugar'' (1R,2S,4R)-2-exo-cyano-7-oxabicyclo[2.2.1]hept-2-endo-yl (1S')-camphanate is also presented.
Univ lausanne,chim sect,ch-1005 lausanne,switzerland.
Record created on 2005-11-09, modified on 2016-08-08