摘要:
Alkynes of sufficiently high nucleophilicity react with electrophilic O-3 under conversion of the alkyne function to a vicinal dicarbonyl function. Contrary to earlier investigations with alkylated or arylated acetylene, products of complete C-C cleavage were not found as primary products, and, beyond that, peroxidic reaction products were absent. Trimethylsilylated alkynes reacted with O-3 either by uptake of two or three O-atoms, but again without C-C cleavage or formation of peroxides. Two particularly electron-rich, symmetrically substituted alkynes revealed strong chemiluminescence during ozonation at low temperature, whereas this behavior was not observed with unsymmetrically substituted alkynes. The results are summarized in terms of a mechanistic discussion.