Asymmetric addition of diethylzinc to ketones promoted by tartaric acid derivatives

The preparation of new sulfonamide ligands derived from L-tartaric acid and camphor sulfonyl chloride are described. The employment in the titanium tetraisopropoxide-promoted enantioselective addition of diethylzinc to ketones has been studied. The best enantiomeric excess is up to 99% with 7mol% catalyst loading at room temperature.