Table 2 |.

Asymmetric cyclopropanation of alkenes by [Fe(P3)Cl] with in situ-generated α-trifluoromethyldiazomethane and various diazo compounds

^aConducted with hydrazone 1 (0.12 mmol) and alkene 2 (0.10 mmol) in the presence of Cs₂CO₃ (0.24 mmol) using [Fe(P3)Cl] as catalyst (2 mol%) in hexanes at 4 °C for 20 h; isolated yields; diastereomeric ratio (d.r.) determined by ¹⁹F NMR analysis of reaction mixture; enantiomeric excess (e.e.) of trans-isomer determined by chiral HPLC.

^bConducted with diazo compound 4 (0.10 mmol) and alkene 2 (0.60 mmol) using [Fe(P3)Cl] as catalyst (2 mol%) in toluene at 23 °C for 24 h; isolated yields; d.r. determined by ¹H NMR analysis of the reaction mixture; e.e. of the major isomer determined by chiral HPLC.

^cAbsolute configuration determined by X-ray crystallography.

^dIn toluene at 23 °C.

^eWith 1 (0.20 mmol).

^fDiazo compound in situ-generated from trisylhydrazone in the presence of Cs₂CO₃ (0.20 mmol).

^gWith 2 (0.12 mmol) in hexanes at 4 °C.

^hAt 80 °C.

ⁱWith 2 (0.20 mmol).

^jIn ethyl acetate.

^kAt 40 °C.