Optically active alpha-phenylethylamine as efficient organocatalyst in the solvent-free reactions between 2,3-butanedione and conjugated nitroolefins

(R)-(+) and (S)-()-1-phenylethylamine have been shown to promote highly diastereoselective and complementary enantioselective formal [3 + 2]carbocyclization reactions between 2, 3-butanedione and conjugated nitroalkenes with formation of enantiomerically rich 2-hydroxy-3- nitrocyclopentanone derivatives. The reactions were carried out both in solvent and under solventfree conditions. The absolute configurations of the products were assigned by X-ray and circular dichroism spectra analyses