Catalytic enantioselective rearrangements and cycloadditions involving ylides from diazo compounds

This review summarizes the background and state of the art (as of June 2000) of catalytic enantioselective rearrangements and cycloadditions involving ylides from diazo compounds. The field is still in its infancy, as until a few years ago it was not considered likely that a catalyst, having decomposed a diazo compound to form an ylide, would still be able to exert an influence on subsequent transformations of the ylide. Recent developments have shown this not to be the case and a new era of synthetically important ylide transformations in organic chemistry has begun where appropriate metal-chiral (nonracemic) ligand combinations are starting to be developed to render these transformations enantioselective.