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Allenes P 0025A Practical Improvement of Crystallization-Induced Asymmetric Transformation of Allene-1,3-dicarboxylates. -Diastereomeric mixtures of allenes (I) bearing naturally abundant chiral alcohols undergo an Et3N-catalyzed epimerization-crystallization between the (R)-and (S)-isomers of the allene moiety in non-polar pentane or hexane solvent to give the pure (R)-allene epimers by repeating the procedure. Pure isomers (II) undergo Diels-Alder cycloaddition reactions with cyclic dienes to give the corresponding bicyclic products as single isomers. -(KATOH, T.; NOGUCHI, C.; KIMURA, H.; FUJIWARA, T.; ICHIHASHI, S.; NISHIDE, K.; KAJIMOTO, T.; NODE*, M.; Tetrahedron: Asymmetry 17 (2006) 20, 2943-2951; Dep. Pharm. Manuf.