Asymmetric cyclopropanation in protic media conducted by chiral bis(hydroxymethyl-dihydrooxazolyl)pyridine-ruthenium catalysts

Cyclopropanation of styrene with diazoacetates, performed in aqueous/organic biphasic media or homogeneous alcoholic media in the combination of toluene by using chiral bis(hydroxymethyldihydrooxazolyl)pyridine-ruthenium catalyst, resulted in high enantiomeric excess up to 96-97% and trans:cis stereoselectivity to 97:3.