INTRAMOLECULAR REACTIONS OF COMPOUNDS DERIVED FROM SUGARS. PART III. HIGH DIASTEREOSELECTION IN THE INTRAMOLECULAR DIELS-ALDER REACTION OF SUGAR BASED 1,7(E,Z),9-DECATRIENES

Article abstract of DOI:10.1016/S0040-4020(01)89126-2

A mixture of tetrachiral deca-1,7E,9-triene 5 and its 7Z isomer 6 was prepared from D-glucose by the use of two Wittig olefination reactions.When 5 or 6 were subjected to intramolecular Diels-Alder reaction under thermal conditions the same, cis-fused octahydronaphtalene enantiomer 9 was formed exclusively.This phenomenom can be explained by Z-->E isomerization of 6 to 5.Similarly, when a mixture of trienones 7 and 8 was heated at 160 deg C the formation of a single product 10 was observed.Stereochemical outcome of the reactions can be rationalized by inspection of the possible conformers leading to transition states.