Exceptional Selectivity in Cyclopropanation Reactions Catalyzed by Chiral Cobalt(II)–Porphyrin Catalysts

Toss the olefin into the porphyrin: The development of chiral cobalt(II)–porphyrin catalysts by straightforward coupling processes has made possible the additions of diazocarbonyl compounds to a broad spectrum of olefins to access functionalized cylopropanes. The cyclopropanation reactions demonstrate high product yields, exceptional diastereoselectivity, and excellent enantiocontrol.