No abstract

1993 oxidation, dehydrogenation, ozonolysis oxidation, dehydrogenation, ozonolysis O 0210 -114Reactions of Alkynes and Carbene Equivalents with Oxo(salen)chromium(V) Complexes.-Alkynes are oxidized slowly by oxo(salen)chromium(V) triflate and related complexes to furnish 1,2-diones such as (II) presumably via metallaoxetene intermediates or related species. A reaction course via similar intermediates is supposed in the reaction of ylides with the Cr(V) complexes giving carbonyl compounds (cf. (IV)) and phosphine oxides. Both the reactions appear to be related mechanistically to the known olefin epoxidation by the same oxometal complexes. -(RIHTER, B.; SRIHARI, S.; HUNTER, S.; MASNOVI, J.; J. Am. Chem. Soc. 115 (1993) 10, 3918-3924; Dep. Chem., Cleveland State Univ., Cleveland, OH 44115, USA; EN)