Abstract
The reaction of [tBu2P(NSiMe3)2-κ2N]Cu(η2-C2H4) (1) with various aryl diazo esters [p-X-C6H4]C(N2)[C(O)R] allowed us to synthesize the corresponding α-carbonyl copper(I) carbene complexes [tBu2P(NSiMe3)2-κ2N]Cu═C[p-X-C6H4][C(O)R] (8), where X = OMe, NO2. The rotation barriers around the Cu−Ccarbene and Ccarbene−CAr bonds or their low limits were determined for some of these compounds by 1H-VT-NMR spectroscopy. Carbene 8g with X = OMe and R = OCH(p-Cl-C6H4)2 was isolated in analytically pure, crystalline form as the first stable representative of this important class of compounds. Its solid-state molecular structure revealed an orthogonal position of the carbene fragment relative to both the ligand plane and the ester C═O group and a remarkably short Cu−Ccarbene distance of 1.822(4) A. Compound 8g reacted with styrene stereoselectively to give the corresponding trans-cyclopropane derivative and [tBu2P(NSiMe3)2-κ2N]Cu(η2-CH2═CHPh). The stoichiometric cyclopropanation of styrene with 8g and the previously de...
Published Version
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