161807-01-8Relevant academic research and scientific papers
Dimesityldioxirane
Sander, Wolfram,Schroeder, Kerstin,Muthusamy, Sengodagounder,Kirschfeld, Andreas,Kappert, Wilhelm,Boese, Roland,Kraka, Elfi,Sosa, Carlos,Cremer, Dieter
, p. 7265 - 7270 (1997)
The preparative scale synthesis of dimesityldioxirane (5) via oxidation of dimesitylcarbene (6) is described. The dioxirane was obtained as colorless crystalline material, completely stable at -20 °C and characterized by spectroscopic methods, X-ray crystallography, and DFT calculations (B3LYP/6-31G(d)). The molecule shows approximately local C2 symmetry with the mesityl rings twisted by ca. 60°. The experimental structural parameters, e.g., the O-O distance of 1.503 A?, are in good agreement with the theoretical values. The relief of steric strain caused by the mesityl groups is discussed in terms of the geometric distortion of the three-membered ring and the mesityl groups. Conformational features of 5 in solution are nicely reflected by measured and calculated (SOS-DFPT) NMR chemical shifts.
Oxidative decomplexation of chromium Fischer carbene complexes induced by dioxiranes
Gibert, Mariona,Ferrer, Marta,Lluch, Anna-Maria,Sanchez-Baeza, Francisco,Messeguer, Angel
, p. 1591 - 1595 (1999)
The reaction course of the oxidative decomplexation of Fischer carbene complexes with dioxiranes was examined. The portionwise addition of 2.2 equiv of dimethyldioxirane (DMD) to Fischer carbene complex 1 afforded ethyl phenylpropiolate in 90% yield. When the reaction was carried out using a CO2-free DMD solution in a N2 atmosphere ester 2 was formed in 40% yield, whereas in the presence of an O2 atmosphere the yield increased to 70%. This same assay performed in the presence of 18O2 atmosphere afforded the ester 2 partially labeled at the C=O moiety (approximately 50% GC-MS) with 18O. On the other hand, treatment of Fischer carbene complex 1 with a [18O2]di- mesityldioxirane solution led to the formation of 18O-labeled CO2 (trapped as BaCO3 and detected by IRMS). From these results it can be suggested that the oxidative decomplexation of Fischer carbene complexes by dioxiranes involves an initial attack of the dioxirane to the metal coordination sphere. In this step a CO ligand is oxidized to CO2 thus leaving an unstable chromium tetracarbonyl intermediate which would react with O2 to give the final ester product and chromium(III) oxide.
