Gold-catalyzed ethylene cyclopropanation

• Silvia G. Rull,
• Andrea Olmos and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2019, 15, 67–71, doi:10.3762/bjoc.15.7

• transfer; cyclopropane; cyclopropylcarboxylate; ethylene cyclopropanation; ethyl diazoacetate; gold catalysis; Introduction Nowadays the olefin cyclopropanation through metal-catalyzed carbene transfer starting from diazo compounds to give olefins constitutes a well-developed tool (Scheme 1a), with an

• = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) catalyzes the ethylene cyclopropanation with ethyl diazoacetate as the carbene precursor, under mild conditions, with moderate yields (ca. 70%, EDA-based). Results and Discussion Diazo compounds N2=CRR’ usually react with metal complexes of groups 8–11 with

• × 320 μm × 0.25 μm. Method: 50 °C × 1.5 min, 10 °C/min, 250 °C × 25 min. Catalytic experiments Ethylene cyclopropanation with EDA. A 175 mL high pressure Fischer–Porter vessel equipped with a manometer and a valve was charged with 0.02 mmol of IPrAuCl (24 mg) and 0.02 mmol of NaBArF4 (17 mg). The vessel