(P)-(+)-[6]Helicene is used as a catalyst in the preparation of α-alkylpyrimidinemethanol by stereoselective addition of isopropylzinc to pyrimidinecarboxaldehyde in presence of helicene isomers. It is also a kind of crystal showing an alternating pattern with pure (-)- revealed by solvent etching of sngle crystals of hexahelicene grown from a racemic solution. These two kinds of crystals are indistinguishable by x-ray diffraction.