The LewisacidcatalyzedintramolecularDiels-Alderreaction of sugar derived trienoates 3 led preferably to bicyclic endo-adducts 4. The best stereoselectivity was observed for cyclization of the L-arabino-trienoate 3b, in which only one isomer (trans) was formed. High pressure (15 kbar) cycloaddition of 3a, 3b, and 3c, led to single stereoisomers 4a, 4b, and 4c in good yields. Conversion of adduct