Hydrodimerization of Cyclic α, β Unsaturated Ketones Promoted by Samarium Iodide

Abstract

An example of hydrodimerization of some cyclic enones by SmI₂/THF system is described. The use of HMPA (hexamethyl phosphoramide), as a copromoter in the system, improves the yield of dimerized products. The X-ray structure of one of these dimers, bis-3,3′(3,5,5-trimethyl cyclohexanone), is also reported.

Notes

Crystal data for (4) C₁₈H₃₀O₂; a = 6.388(2), b = 6.398(2), c = 11.439(2) å, α = 97.89, β = 99.43, γ = 114.19, triclinic, space group P 1, Z = 1 F (000) = 154, Dx = 1.128 mg. m⁻³, λ (Cu-Kα) = 1.54178 Δ° μ(Cu-Kα) = 5.48 cm⁻¹, T° = 296 K. Data were collected on a Nicolet P3/F diffractometer with Ni-filter monochromatized Cu-Kα radiation. The structure was solved by direct methods (SIR92, Altomare A. Appl. Cryst. 1994 27 435) and refined by full matrix least-square procedure using SHELXTL (Seldrick, G. M. SHELXTL. PC User Manual Siemens Analytical X-Ray instruments, Madisson, Wisconsin, U.S.A. 1990). In the final cycles of refinement all non-hydrogen atoms were treated anisotropically. The hydrogen atoms attached to carbon atoms were included as fixed contributions, the function minimized was Σω (|F₀| - |F_c|)², where ω⁻¹ = σ² (F) + 0.0008 F₀ ² resulting in R = 0.062, Rw = 0.068 and S = 1.43.