Highly enantioselective synthesis of cyclopropylphosphonates catalyzed by chiral ruthenium porphyrins

reaction: see text] The asymmetric addition of diisopropyl diazomethylphosphonate to styrene derivatives was carried out by using chiral ruthenium porphyrins as catalysts. The reaction proceeded under mild conditions and gave trans-cyclopropylphosphonates with good yields and high ee's (up to 92%). A progressive increase for stereochemical effectiveness exists between enantiomeric excess and the number of chiral goups linked to ruthenium porphyrins.