Gold-catalyzed ethylene cyclopropanation.

Ethylene can be directly converted into ethyl 1-cyclopropylcarboxylate upon reaction with ethyl diazoacetate (NCHCOEt, EDA) in the presence of catalytic amounts of IPrAuCl/NaBAr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene; BAr = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate).

The Elusive Palladium-Diazo Adduct Captured: Synthesis, Isolation and Structural Characterization of [(ArNHC-PPh )Pd(η -N C(Ph)CO Et)].

The first example of a diazo palladium adduct is reported. The complexes [(ArNHC-PPh )M(η -N C(Ph)CO Et)] (M=Ni, 3; M=Pd, 4; ArNHC-PPh =3-(2,6-diisopropylphenyl)-1-[(diphenylphosphino)ethyl]imidazol-2-ylidene) were prepared by ligand exchange with styrene-coordinated precursors [(ArNHC-PPh )M(styrene)] (M=Ni, 1; M=Pd, 2). Complex 4 was fully characterized, including X-ray analyses; this constitutes the first example of a diazo adduct compound with palladium, thereby closing the gap between Groups 8 and 10 regarding this type of compounds.