Highly Stereoselective Cyclopropanation of α,β‐Unsaturated Carbonyl Compounds with Methyl (Diazoacetoxy)acetate Catalyzed by a Chiral Ruthenium(II) Complex

Tantalizing triangles: The title reaction gives bicarbonyl cyclopropane products that can lead to versatile intermediates with high yields and stereoselectivities. This system was also applied to the enantioselective total synthesis of spiro cyclopropane oxindole, an HIV-1 nonnucleoside reverse transcriptase inhibitor.