Highly enantioselective synthesis of cyclopropylphosphonates catalyzed by chiral ruthenium porphyrins

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.