On the synthesis of nitrilium salts from nitriles and chloroformates

Article abstract of DOI:10.1055/s-1993-25876

Nitriles react with methyl or ethyl chloroformate (2a,b) and antimony(V) chloride to give high yields of N-methyl-, or N-ethylnitrilium hexachloroantimonates 3,4. With butyl chloroformate (2c) N-(1-methylpropyl)nitrilium salts 6 are obtained. These products arise from a 2-butyl cation, which is formed prior to alkylation of the nitrile. Isobutyl chloroformate (2d), (2-tert-butylcyclohexyl) chloroformate (2e), menthyl chloroformate (2f), 2,2-dimethylpropyl chloroformate (2g), and 3-methylbutyl chloroformate (2h) react with nitriles to give N-tert-alkylnitrilium salts, 11,13,15,19, which were characterized by hydrolysis to amides. With phenyl chloroformate (2i) benzonitriles react in a 1:2 ratio to furnish 2-phenoxy-1,3,5-oxadiazinium salts 21.