On the Reaction of α-Chlorobenzylic Cations with Isocyanates

Article abstract of DOI:10.1002/prac.19923340804

Isocyanates react as N-nucleophiles with α-chlorobenzylic cations (2) to give 1-oxoisoindolium salts (5).From the reaction of benzotrichlorides with SbCl5 and isocyanates the extremely reactive hexachloroantimonates 5 with R²=Cl are isolated.Hydrolysis of these cyclic N-acyl iminium salts affords phthalimides 6.Reaction of 5k with dimethylcyanamide gives the 2-azoniaallene salt 13. p-Tolyl isocyanate is Friedel-Crafts alkylated by p-chlorobenzotrichloride (1i) in the presence of SbCl5 to furnish the 1,3-oxadiazonium salt 7, which is hydrolyzed to give the benzophenone 9.With ethanol the acetals 10 and 11 are formed from 7.