Key points are not available for this paper at this time.
The enantiomers of a bis5helicenediol ligand (5HELOL) have been synthesized in appreciable amounts by a procedure in which key steps are the union of p -benzoquinone with an enol ether of 3-acetylphenanthrene and the displacement of phenol and phenol ether functions by alcohols (the Russig−Laatsch reaction). This diol catalyzes the addition of diethylzinc to aldehydes and gives nonracemic alcohols with enantiomeric excesses as high as 81%. The stereoselectivities and yields are much greater than when the catalyzing diol is BINOL. The enantioselectivities are greater also than those of other reactions catalyzed by helicene ligands.
Dreher et al. (Sun,) studied this question.