UEBER DIE SI-N-BINDUNG XLIV. DIE UMSETZUNG VON BENZOPHENON MIT BIS- UND TRIS(TRIMETHYLSILYL)AMIN

Article abstract of DOI:10.1016/0022-328X(85)87290-9

1,1,3-Triphenyl-1H-isoindole (I) is obtained in yields up to 66percent by reacting benzophenone with tris(trimethylsilyl)amine or with bis(trimethylsilyl)amine and chlorotrimethylsilane in the presence of catalytic amounts of a Lewis acid at 230-280 deg C in a sealed tube or with equimolar amounts of a Lewis acid at 210 deg C without using a sealed tube.At temperatures above 280 deg C the same reactions yiels mixtures of I with 1,2,3-triphenyl-2H-isoindole (II), whose fraction can reach 25percent of the isoindole mixture.Mechanistic investigations on the new isoindole synthesis indicated, that azaallenium cations are involved as intermediates.