α-Hydroxy esters as inexpensive chiral auxiliaries in rhodium(II)-catalyzed cyclopropanations with vinyldiazomethanes

Article abstract of DOI:10.1016/0040-4039(91)80206-L

High levels of asymmetric induction were achieved in rhodium(II) catalyzed cyclopropanations with chiral vinyldiazomethanes. (R)-(-)-Pantolactone is the most effective chiral auxiliary, but other α-hydroxy esters also give reasonable levels of diastereose