Totally Regio- and Stereoselective Behavior of Mono- and Diactivated Cyclic Alkenes in the Lu Reaction: Synthesis of Enantiopure Functionalized Cyclopentanes

5-Alkoxyfuran-2(5H)-ones and their optically pure 3-p-tolylsulfinyl derivatives, synthetic equivalents of the acyclic esters, react with dipoles generated from allenoates and PPh3 (Lu reaction), in a completely regioselective, π-facial selective and endo-selective manner, yielding bicyclic adducts, which are easily converted into optically pure highly substituted cyclopentane derivatives.