Synthesis of diethyl 2-methyl-bicyclo[3.1.1]hept-2-ene-6,6-dicarboxylate by Pd-catalyzed intramolecular allylic alkylation. Stereoselective preparation of its optically homogeneous form from R-(−)-carvone

A new route to racemic diethyl 2-methyl-bicyclo[3.1.1]hept-2-ene-6,6-dicarboxylate (±)-1a by means of a palladium-catalyzed intramolecular allylic alkylation exercised on malonate-ester derivatives has been developed from R-(−)-carvone. The stereocontrolled synthesis of the enantiomerically pure (−)-1b by application of a six-step reactions sequence with a 28% overall yield from acetal 8, has been accomplished.